via the Linux tool.
- Add Linux shim to ipmi(4)
- Create a partitions file to linprocfs to make Linux fdisk see
disks. This file is dynamic so we can see disks come and go.
- Convert msdosfs to vfat in mtab since Linux uses that for
msdosfs.
- In the Linux mount path convert vfat passed in to msdosfs
so Linux mount works on FreeBSD. Note that tasting works
so that if da0 is a msdos file system
/compat/linux/bin/mount /dev/da0 /mnt
works.
- fix a 64it bug for l_off_t.
Grabing sh, mount, fdisk, df from Linux, creating a symlink of mtab to
/compat/linux/etc/mtab and then some careful unpacking of the Linux bmc
update tool and hacking makes it work on newer Dell boxes. Note, probably
if you can't figure out how to do this, then you probably shouldn't be
doing it :-)
When a vt switch occurs the irq handler is uninstalled. Interrupts
and the state tracking of what was enabled/disabled wasn't working
properly. This should resolve the reports of "slow windows" after a
vt switch, among other things. The radeon 2d driver seems to work a
bit more correctly than the Intel driver. With the Intel driver,
vblank interrupts will be enabled at system startup and will only
be disabled after an additional modeset (vt switch, dpms, randr event).
With this patch, I am able to run glxgears synced to vblank and
vt switch while it is running without ill effects.
MFC after: 3 days
prevent individual transactions from crossing a 4GB address boundary. Due
to bus_size_t type limitations, the driver uses a 2GB boundary in PAE
kernels.
Reviewed by: scottl
MFC after: 1 week
quirk requiring it to be enabled even when using MSI. This makes
the latter work again after r189285.
- Remove a comment which no longer applies since r190194.
filtering handle this. Introduce a new function msk_rxfilter that
handles Rx filter configuration and multicast setup as well as
promiscuous mode. This simplifies code a lot.
Promiscuous mode always have preference to any other Rx
filtering so don't disable the mode when ALLMULTI is set.
it is right for only a tiny fraction of these devices and this
wild-card entry is too broad.
# I run a kernel without this entry at all without ill effects...
The tick routine was not being restarted in the init_locked routine
which could resulted in loss of carrier when updating the MTU.
Submitted by: Navdeep Parhar at Chelsio
MFC after: 3 weeks
- If boot verbose, print asicrev, chiprev and bus type on attach.
- For PCI Express devices:
1) Adjust max read request size to 4Kbytes
2) Turn on FIFO_LONG_BURST in RDMA during bge_blockinit()
Though 1) does not seem to have much to do with the poor TX performance
observed on PCI Express bge(4), 2) does fix the problem. [1]
- Nuke the RX CPU self-diag, which prevents working cards from working
(Linux tg3 does not have this diag neither does OpenBSD's bge(4)).
The increasing of the firmware handshaking timeout to 20000 retries
done as part of the original commit isn't merged as way already have a
way higher BGE_TIMEOUT of 100000.
PR: 119361 [1]
Obtained from: tg3 via DragonflyBSD [1], DragonflyBSD
Workaround for buggy USB hardware not handling new SETUP packet before STATUS
stage is complete, this allows xfers to endpoint0 to return a short frame.
Submitted by: Hans Petter Selasky
Reported by: me
Workaround for buggy USB hardware not handling new SETUP packet before STATUS
stage is complete, this allows xfers to endpoint0 to return a short frame.
Submitted by: Hans Petter Selasky
Reported by: me
- Move tunable defines into usb_core.h and dependancy towards usb_defs.h
- Leave hardcoded defines in "usb_defs.h".
- Allow overriding all tunable defines.
- Add more customisable typedefs.
- Correct maximum device number.
Submitted by: Hans Petter Selasky
It seems I didn't fix this issue before committing teken to the tree. My
initial idea was to somehow add an error mechanism to instruct the video
driver author to increase T_NUMCOL when using very big terminals. It
turns out we have platforms where we have gigantic consoles on systems
like the Apple PowerMac G5, which means we crash there right now.
Just ignore tabstops placed beyond column 160. Just force tabs to be
placed on each 8 columns.
Reported by: nwhitehorn
supported with these pseudo-PHYs. The MIIF_NOLOOP flag currently triggers
nothing but hopefully will be respected by mii_phy_setmedia() later on.
- Don't add IFM_NONE as isolation isn't supported by these pseudo-PHYs.
- Use mii_phy_add_media() instead of mii_add_media() so the latter can
be eventually retired.
driver in Linux 2.6. uscanner was just a simple wrapper around a fifo and
contained no logic, the default interface is now libusb (supported by sane).
Reviewed by: HPS
after vt switch or suspend. I can't really test this on Intel right now
but I think I've heard reports of it on radeon as well. I can't break
it on the radeon here.
MFC after: 3 days
o break out version-related code to simplify rev'ing the protocol
o add parameter validation macros so checks that appear multiple places
are consistent (and easy to change)
o add protocol version check when looking for a scan candidate
o improve scan debug output format
o rewrite beacon update handling to calculate a bitmask of changed values
and pass that down through the driver callback so drivers can optimize work
o do slot bounds check before use when parsing received beacons
or URB_FUNCTION_CLASS_xxx with HAL preemption lock that means it's
non-sleepable during USB requests though usb2_do_request() requires a
sleep so it needs to send queries to the default pipe without those
interfaces to avoid sleep.
Obtained from: Hideotshi Shimokawa
This update is based on comments from Hidetoshi.
Changeset 183550 removed the call to crom_load() in fw_busreset(). Restore
that call such that the Configuration ROM is valid.
Stash and update fwdev settings in fw_explore_node() so that negotiation
works again.
Fix regression issue in the USB file system interface.
- Use cdev_privdata pointer as indicator of correct file handle.
- Remove redundant FIFO opened flags.
Don't send ZLP at close for ulpt and uscanner devices as this causes some
models to stop working. This reverts back to the USB1 behaviour.
Submitted by: Hans Petter Selasky
This code is heavily inspired by Takanori Watanabe's experimental SMP patch
for i386 and large portion was shamelessly cut and pasted from Peter Wemm's
AP boot code.
implement CD input in hardware, while unconditional showing it confuse users.
Also it was made in the way that sometimes improper with present driver.
Add patch for ALC268 based Acer TM5320 to make headphones jack sensing work.
Default configuration defines two separate playback associations, which
current driver unable to trace properly due to order they are defined and
limited codec uniformity.
Submitted by: G. Mirov <g.mirov AT gmail.com>
C-NET(PC) has a cfe at location 1 that has both an odd irq mask (it
matches pc98 machines, so maybe it was a flag for pc98 operation) as
well as a memory map. Since this driver doesn't know how to cope, we
start with cfe2, which is purely an I/O space mapped and that seems to
make it work. I say 'seems' here, because the card I have doesn't
seem to have the right dongle for full testing...
(1) Fix pcib_read/write_config prototypes.
(2) When contrainting a resource request for a 'subtractive' bridge,
it is important to select a range outside the base/limit
registers, since those are the only values known to not
possibly work. On my HP laptop, the base bridge excludes I/O
ports 0xa000-0xafff, however that was the range we were passing
up the tree. Instead, when a range spans the "hole" we now
arbitrarily pick the range just above the hole to allocate from.
All of my rl and xl cards, at a minimum, started working again on this
laptop with those fixes.
look like a temperature.
This driver will most likely be renamed to something more meaningful in
the near future.
Submitted by: nork
MFC after: 2 weeks
o add 9280 attach that sets up ini, cal, etc.
o new rf backend for 9280 and later parts
o split ini setup and spur mitigation support out to methods
and provide 9280-specific support
o minor fixups to shared code to handle 9280-specific work
Obtained from: Atheros (ini values and some code)
both disks, or if we should suppress the slave drive. Default to
suppressing the slave, in the case that this REQIURED tuple turns out
to not actually be present...
Based on the HAL preemption lock there is a problem on SMP machines
and causes a panic.
o When a device detached the current tactic to detach NDIS USB driver is
to call SURPRISE_REMOVED event. So it don't need to call
ndis_halt_nic() again. This fixes some page faults when some drivers
work abnormal.
o it assumes now that URB_FUNCTION_BULK_OR_INTERRUPT_TRANSFER is in
DISPATCH_LEVEL (non-sleepable) and as further work
URB_FUNCTION_VENDOR_XXX and URB_FUNCTION_CLASS_XXX should be.
Reviewed by: Hans Petter Selasky <hselasky_at_freebsd.org>
Tested by: Paul B. Mahol <onemda_at_gmail.com>
More HID parsing fixes for usb mice.
- be less strict on the last HID item usage.
- preserve item size and count accross items
- improve default HID usage selection.
Tested by: ache
Submitted by: Hans Petter Selasky
o Header file cleanup.
o bus_dma(9) conversion.
- Removed all consumers of vtophys(9) and converted to use
bus_dma(9).
- Typhoon2 functional specification says the controller supports
64bit DMA addressing. However all Typhoon controllers are known
to lack of DAC support so 64bit DMA support was disabled.
- The hardware can't handle more 16 fragmented Tx DMA segments so
teach txp(4) to collapse these segments to be less than 16.
- Added Rx buffer alignment requirements(4 bytes alignment) and
implemented fixup code to align receive frame. Previously
txp(4) always copied Rx frame to align it on 2 byte boundary
but its copy overhead is much higher than unaligned access on
i386/amd64. Alignment fixup code is now applied only for
strict-alignment architectures. With this change i386 and
amd64 will get instant Rx performance boost. Typhoon2 datasheet
mentions a command that pads arbitrary bytes in Rx buffer but
that command does not work.
- Nuked pointer trick in descriptor ring. This does not work on
sparc64 and replaced it with bcopy. Alternatively txp(4) can
embed a 32 bits index value into the descriptor and compute
real buffer address but it may make code complicated.
- Added endianness support code in various Tx/Rx/command/response
descriptor access. With this change txp(4) should work on all
architectures.
o Added comments for known firmware bugs(Tx checksum offloading,
TSO, VLAN stripping and Rx buffer padding control).
o Prefer faster memory space register access to I/O space access.
Added fall-back mechanism to use alternative I/O space access.
The hardware supports both memory and I/O mapped access. Users
can still force to use old I/O space access by setting
hw.txp.prefer_iomap tunable to 1 in /boot/loader.conf.
o Added experimental suspend/resume methods.
o Nuke error prone Rx buffer handling code and implemented local
buffer management with TAILQ. Be definition the controller can't
pass the last received frame to host if no Rx free buffers are
available to use as head and tail pointer of Rx descriptor ring
can't have the same value. In that case the Rx buffer pointer in
Rx buffer ring still holds a valid buffer and txp_rxbuf_reclaim()
can't fill Rx buffers as the first buffer is still valid. Instead
of relying on the value of Rx buffer ring, introduce local buffer
management code to handle empty buffer situation. This should fix
a long standing bug which completely hangs the controller under
high network load. I could easily trigger the issue by sending 64
bytes UDP frames with netperf. I have no idea how this bugs was
not fixed for a long time.
o Converted ithread interrupt handler to filter based one.
o Rearranged txp_detach routine such that it's now used for general
clean-up routine.
o Show sleep image version on device attach time. This will help
to know what action should be taken depending on sleep image
version. The version information in datasheet was wrong for newer
NV images so I followed Linux which seems to correctly extract
version numbers from response descriptors.
o Firmware image is no longer downloaded in device attach time. Now
it is reloaded whenever if_init is invoked. This is to ensure
correct operation of hardware when something goes wrong.
Previously the controller always run without regard to running
state of firmware. This change will add additional controller
initialization time but it give more robust operation as txp(4)
always start off from a known state. The controller is put into
sleep state until administrator explicitly up the interface.
o As firmware is loaded in if_init handler, it's now possible to
implement real watchdog timeout handler. When watchdog timer is
expired, full-reset the controller and initialize the hardware
again as most other drivers do. While I'm here use our own timer
for watchdog instead of using if_watchdog/if_timer interface.
o Instead of masking specific interrupts with TXP_IMR register,
program TXP_IER register with the interrupts to be raised and
use TXP_IMR to toggle interrupt generation.
o Implemented txp_wait() to wait a specific state of a controller.
o Separate boot related code from txp_download_fw() and name it
txp_boot() to handle boot process.
o Added bus_barrier(9) to host to ARM communication.
o Added endianness to all typhoon command processing. The ARM93C
always expects little-endian format of command/data.
o Removed __STRICT_ALIGNMENT which is not valid on FreeBSD.
__NO_STRICT_ALIGNMENT is provided for that purpose on FreeBSD.
Previously __STRICT_ALIGNMENT was unconditionally defined for
all architectures.
o Rewrote SIOCSIFCAP ioctl handler such that each capability can be
controlled by ifconfig(8). Note, disabling VLAN hardware tagging
has no effect due to the bug of firmware.
o Don't send TXP_CMD_CLEAR_STATISTICS to clear MAC statistics in
txp_tick(). The command is not atomic. Instead, just read the
statistics and reflect saved statistics to the statistics.
dev.txp.%d.stats sysctl node provides detailed MAC statistics.
This also reduces a lot of waste of CPU cycles as processing a
command ring takes a very long time on ARM93C. Note, Rx
multicast and broadcast statistics does not seem to right. It
might be another bug of firmware.
o Implemented link state change handling in txp_tick(). Now sending
packets is allowed only after establishing a valid link. Also
invoke link state change notification whenever its state is
changed so pseudo drivers like lagg(4) that relies on link state
can work with failover or link aggregation without hacks.
if_baudrate is updated to resolved speed so SNMP agents can get
correct bandwidth parameters.
o Overhauled Tx routine such that it now honors number of allowable
DMA segments and checks for 4 free descriptors before trying to
send a frame. A frame may require 4 descriptors(1 frame
descriptor, 1 or more frame descriptors, 1 TSO option descriptor,
one free descriptor to prevent descriptor wrap-around) at least
so it's necessary to check available free descriptors prior to
setting up DMA operation.
o Added a sysctl variable dev.txp.%d.process_limit to control
how many received frames should be served in Rx handler. Valid
ranges are 16 to 128(default 64) in unit of frames.
o Added ALTQ(4) support.
o Added missing IFCAP_VLAN_HWCSUM as txp(4) can offload checksum
calculation as well as VLAN tag insertion/stripping.
o Fixed media header length for VLAN.
o Don't set if_mtu in device attach, it's already set in
ether_ifattach().
o Enabled MWI.
o Fixed module unload panic when bpf listeners are active.
o Rearranged ethernet address programming logic such that it works
on strict-alignment architectures.
o Removed unused member variables in softc.
o Added support for WOL.
o Removed now unused TXP_PCI_LOMEM/TXP_PCI_LOIO.
o Added wakeup command TXP_BOOTCMD_WAKEUP definition.
o Added a new firmware version query command, TXP_CMD_READ_VERSION.
o Removed volatile keyword in softc as bus_dmamap_sync(9) should
take care of this.
o Removed embedded union trick of a structure used to to access
a pointer on LP64 systems.
o Added a few TSO related definitions for struct txp_tcpseg_desc.
However TSO is not used at all due to the limitation of hardware.
o Redefined PKT_MAX_PKTLEN to theoretical maximum size of a frame.
o Switched from bus_space_{read|write}_4 to bus_{read|write}_4.
o Added a new macro TXP_DESC_INC to compute next descriptor index.
Tested by: don.nasco <> gmail dot com
filesystem supports additional operations using shared vnode locks.
Currently this is used to enable shared locks for open() and close() of
read-only file descriptors.
- When an ISOPEN namei() request is performed with LOCKSHARED, use a
shared vnode lock for the leaf vnode only if the mount point has the
extended shared flag set.
- Set LOCKSHARED in vn_open_cred() for requests that specify O_RDONLY but
not O_CREAT.
- Use a shared vnode lock around VOP_CLOSE() if the file was opened with
O_RDONLY and the mountpoint has the extended shared flag set.
- Adjust md(4) to upgrade the vnode lock on the vnode it gets back from
vn_open() since it now may only have a shared vnode lock.
- Don't enable shared vnode locks on FIFO vnodes in ZFS and UFS since
FIFO's require exclusive vnode locks for their open() and close()
routines. (My recent MPSAFE patches for UDF and cd9660 already included
this change.)
- Enable extended shared operations on UFS, cd9660, and UDF.
Submitted by: ups
Reviewed by: pjd (ZFS bits)
MFC after: 1 month
legal in the spec. Add newline to the verbose messages we print when
debugging when this happens. The Hitachi HT-4840-11 is the only card
to hit these in years, and it works well enough if we're liberal about
what we accept.
this fixes geom_redboot on boards that have multiple parts/regions as it
uses the value to locate the FIS directory which is in the last erase
region of flash
Firmware upgraded to 7.1.0 (from 5.0.0).
T3C EEPROM and SRAM added; Code to update eeprom/sram fixed.
fl_empty and rx_fifo_ovfl counters can be observed via sysctl.
Two new cxgbtool commands to get uP logic analyzer info and uP IOQs
Synced up with Chelsio's "common code" (as of 03/03/09)
Submitted by: Navdeep Parhar at Chelsio
Reviewed by: gnn
MFC after: 2 weeks
the PORTEN and MEMEN bits in the command register than to zero the
bars.
Use pci_write_ivar directly instead of a one-line wrapper that adds no
value.
Track verbosity changes in pci.
Remove a stray blank line.
After I imported libteken into the source tree, I noticed syscons didn't
store the cursor position inside the terminal emulator, but inside the
virtual terminal stat. This is not very useful, because when you
implement more complex forms of line wrapping, you need to keep track of
more state than just the cursor position.
Because the kernel messages didn't share the same terminal emulator as
ttyv0, this caused a lot of strange things, like kernel messages being
misplaced and a missing notification to resize the terminal emulator for
kernel messages never to be resized when using vidcontrol.
This patch just removes kernel_console_ts and adds a special parameter
to te_puts to determine whether messages should be printed using regular
colors or the ones for kernel messages.
Reported by: ache
Tested by: nyan, garga (older version)
We should just leave the underlying TTY objects alone when scrolling
around in KDB. It should be handled by Syscons exclusively.
Reported by: pluknet gmail com
get default next page configuration. While I'm here explicitly set
IP1000PHY_ANAR_CSMA bit. This bit is read-only and always set
by hardware so setting it has no effect but it would clear the
intention. With this change controllers that couldn't establish
1000baseT link should work.
PR: kern/130846
mapping. The tunable is OFF for all controllers except RTL8169SC
family. RTL8169SC seems to require more magic to use memory
register mapping. r187483 added a fix for RTL8169SCe controller but
it does not looke like fix other variants of RTL8169SC.
Tested by: Gavin Stone-Tolcher g.stone-tolcher <> its dot uq dot edu dot au
o correct dBm<->mW conversion logic
o set net80211 TXPMGT capability only if driver reports it is capable
PR: kern/132342
Submitted by: "Paul B. Mahol" <onemda@gmail.com>
Fix bugs and improve HID parsing.
- fix possible memory leak found
- fix possible NULL pointer access
- fix possible invalid memory read
- parsing improvements
- reset item data position when a new report ID is detected.
Submitted by: Hans Petter Selasky
Tested on an HD3850 (RV670) on loan from Warren Block.
Currently, you need one of the following for this to be useful:
x11-drivers/xf86-video-radeonhd-devel (not tested)
xf86-video-ati from git (EXA works, xv is too fast)
xf86-video-radeonhd from git (EXA works, xv works)
There is no 3d support available from dri just yet.
MFC after: 2 weeks
o add Transaction Translator support (still missing ISOC xfers)
o add EHCI_SCFLG_BIGEMMIO flag to force big-endian byte-select to be
set in USBMODE
o split reset work into new public routine ehci_reset so bus shim drivers
can force big-endian byte-select before ehci_init
o enable TT and big-endian MMIO
o force a reset before ehci_init to get byte-select setup
Also go back to using USB_EHCI_BIG_ENDIAN_DESC at compile time to enable the
byteswapping and reduce diffs to the original commits.
This fixes the new USB stack on the Cambria board.
o implement URB_FUNCTION_ABORT_PIPE handling.
o remove unused code related with canceling the timer list for USB
drivers.
o whitespace cleanup and style(9)
Obtained from: hps's original patch
entry is a specific entry to override the generic NetMos entry so that
puc(4) will leave this device alone and let uart(4) claim it.
Submitted by: Navdeep Parhar nparhar @ gmail
Reviewed by: marcel
MFC after: 1 week
when determining the size of a BAR by writing all 1's to the BAR and
reading back the result, always operate on the full 64-bit size.
Reviewed by: imp
MFC after: 1 month
flag when calling bus_alloc_resource() to allocate resources from a parent
PCI bridge. For PCI-PCI bridges this asks the bridge to satisfy the
request using the prefetchable memory range rather than the normal
memory range.
Reviewed by: imp
Reported by: scottl
MFC after: 1 week
BAR could be allocated twice by different children of a vgapci0 device.
To fix this, change the vgapci0 device to track references on its associated
resources so that they are only allocated once from the parent PCI bus and
released when no children are using them. Previously this leaked a small
amount of KVA on at least some architectures.
We now explicitly enable INTx during bus_setup_intr() if it is needed.
Several of the ata drivers were managing this bit internally. This is
better handled in pci and it should work for all drivers now.
We also mask INTx during bus_teardown_intr() by setting this bit.
Reviewed by: jhb
MFC after: 3 days
- Added missing firmware for 5709 A1 controllers.
- Changed some debug statistic variable names to be more consistent.
Submitted by: davidch
MFC after: Two weeks
A while back, Warner changed the PCI bus code to reserve resources when
enumerating devices and simply give devices the previously allocated
resources when they call bus_alloc_resource(). This ensures that address
ranges being decoded by a BAR are always allocated in the nexus0 device
(or whatever device the PCI bus gets its address space from) even if a
device driver is not attached to the device. This patch extends this
behavior further:
- To let the PCI bus distinguish between a resource being allocated by
a device driver vs. merely being allocated by the bus, use
rman_set_device() to assign the device to the bus when it is owned
by the bus and to the child device when it is allocated by the child
device's driver. We can now prevent a device driver from allocating
the same device twice. Doing so could result in odd things like
allocating duplicate virtual memory to map the resource on some
archs and leaking the original mapping.
- When a PCI device driver releases a resource, don't pass the request
all the way up the tree and release it in the nexus (or similar device)
since the BAR is still active and decoding. Otherwise, another device
could later allocate the same range even though it is still in use.
Instead, deactivate the resource and assign it back to the PCI bus
using rman_set_device().
- pci_delete_resource() will actually completely free a BAR including
attemping to disable it.
- Disable BAR decoding via the command register when sizing a BAR in
pci_alloc_map() which is used to allocate resources for a BAR when
the BIOS/firmware did not assign a usable resource range during boot.
This mirrors an earlier fix to pci_add_map() which is used when to
size BARs during boot.
- Move the activation of I/O decoding in the PCI command register into
pci_activate_resource() instead of doing it in pci_alloc_resource().
Previously we could actually enable decoding before a BAR was
initialized via pci_alloc_map().
Glanced at by: bsdimp
This addresses interrupt storms that were noticed after enabling MSI
in drm. I think this is due to a loose interpretation of the PCI 2.3
spec, which states that a function using MSI is prohibitted from using
INTx. It appears that some vendors interpretted that to mean that they
should handle it in hardware, while others felt it was the drivers
responsibility.
This fix will also likely resolve interrupt storm related issues with
devices other than drm.
Reviewed by: jhb@
MFC after: 3 days
name i2c-address instead of reg. Change the OFW I2C probe to check both
locations for the address.
Submitted by: Marco Trillo
Reported by: Justin Hibbits
ready status. Most of controllers managed to issue coommand and set BUSY
bit almost simultaneously, before we will read it, but at least JMicron JMB363
don't. Ignore timeout errors to keep old behavior when error there was
impossible.
For me this fixes timeout errors on the first command after channel attach
or reinit. Boot in my case is not affected, as there is much time passing
between reset and next command giving reset time to complete.
done in other places. Until we have no support for command queueing we have
no any benefit from FBS, while enabling it only here somehow leads to
"port not ready" errors on Intel 63XXESB2 controller.
Tested by: Larry Rosenman <ler AT lerctr.org>
and partially r188903. Revert breaks new drives detection on reinit to the
state as it was before me, but fixes series of new bugs reported by some
people.
Unconditional queueing of ata_completed() calls can lead to deadlock if
due to timeout ata_reinit() was called at the same thread by previous
ata_completed(). Calling of ata_identify() on ata_reinit() in current
implementation opens numerous races and deadlocks.
Problems I was touching here are still exist and should be addresed, but
probably in different way.
drivers' probe routines. It allows not to sleep and so not drop Giant inside
ata_identify() critical section and so avoid crash if it reentered on
request timeout. Reentering of probe call checked inside of it.
Give device own knowledge about it's type (ata/atapi/atapicam). It is not
a good idea to ask channel status for device type inside ata_getparam().
Add softc memory deallocation on device destruction.
at irq install/uninstall time, but when we vt switch, we uninstall the
irq handler. When the irq handler is reinstalled, the modeset ioctl
happens first. The modeset ioctl is supposed to tell us that we can
disable vblank interrupts if there are no active consumers. This will
fail after a vt switch until another modeset ioctl is called via dpms
or xrandr. Leading to cases where either interrupts are on and can't
be disabled, or worse, no interrupts at all.
MFC after: 2 weeks
