freebsd kernel with SKQ
e4ec9bc987
define). Fix stupidity wrt checking whether we've gone to LOOP_PDB_RCVD loopstate- it's okay to be greater than this state. D'oh! Protect calls to isp_pdb_sync and isp_fclink_state with IS_FC macros. Completely redo mailbox command routine (in preparation to make this possibly wait rather than poll for completion). Make a major attempt to solve the 'lost interrupt' problem 1. Problem The Qlogic cards would appear to 'lose' interrupts, i.e., a legitimate regular SCSI command placed on the request queue would never complete and the watchdog routine in the driver would eventually wakeup and catch it. This would typically only happen on Alphas, although a couple folks with 700MHz Intel platforms have also seen this. For a long time I thought it was a foulup with f/w negotiations of SYNC and/or WIDE as it always seemed to happen right after the platform it was running on had done a SET TARGET PARAMETERS mailbox command to (re)enable sync && wide (after initially forcing ASYNC/NARROW at startup). However, occasionally, the same thing would also occur for the Fibre Channel cards as well (which, ahem, have no SET TARGET PARAMETERS for transfer mode). After finally putting in a better set of watchdog routines for the platforms for this driver, it seemed to be the case that the command in question (usually a READ CAPACITY) just had up and died- the watchdog routine would catch it after ~10 seconds. For some platforms (NetBSD/OpenBSD)- an ABORT COMMAND mailbox command was sent (which would always fail- indicating that the f/w denied knowledge of this command, i.e., the f/w thought it was a done command). In any case, retrying the command worked. But this whole problem needed to be really fixed. 2. A False Step That Went in The Right Direction The mailbox code was completely rewritten to no longer try and grab the mailbox semaphore register and to try and 'by hand' complete async fast posting completions. It was also rewritten to now have separate in && out bitpatterns for registers to load to start and retrieve to complete. This means that isp_intr now handles mailbox completions. This substantially simplifies the mailbox handling code, and carries things 90% toward getting this to be a non-polled routine for this driver. This did not solve the problem, though. 3. Register Debouncing I saw some comments in some errata sheets and some notes in a Qlogic produced Linux driver (for the Qlogic 2100) that seemed to indicate that debouncing of reads of the mailbox registers might be needed, so I added this. This did not affect the problem. In fact, it made the problem worse for non-2100 cards. 5. Interrupt masking/unmasking The driver *used* to do a substantial amount of masking/unmasking of the interrupt control register. This was done to make sure that the core common code could just assume it would never get pre-empted. This apparently substantially contributed to the lost interrupt problem. The rewrite of the ICR (Interrupt Control Register), which is a separate register from the ISR (Interrupt Status Register) should not have caused any change to interrupt assertions pending. The manual does not state that it will, and the register layout seems to imply that the ICR is just an active route gate. We only enable PCI Interrupts and RISC Interrupts- this should mean that when the f/w asserts a RISC interrupt and (and the ICR allows RISC Interrupts) and we have PCI Interrupts enabled, we should get a PCI interrupt. Apparently this is a latch- not a signal route. Removing this got rid of *most* but not all, lost interrupts. 5. Watchdog Smartening I made sure that the watchdog routine would catch cases where the Qlogic's ISR showed an interrupt assertion. The watchdog routine now calls the interrupt service routine if it sees this. Some additional internal state flags were added so that the watchdog routine could then know whether the command it was in the middle of burying (because we had time it out) was in fact completed by the interrupt service routine. 6. Occasional Constipation Of Commands.. In running some very strenous high IOPs tests (generating about 11000 interrupts/second across one Qlogic 1040, one Qlogic 1080 and one Qlogic 2200 on an Alpha PC164), I found that I would get occasional but regular 'watchdog timeouts' on both the 1080 and the 2100 cards. This is under FreeBSD, and the watchdog timeout routine just marks the command in error and retries it. Invariably, right after this 'watchdog timeout' error, I'd get a command completion for the command that I had thought timed out. That is, I'd get a command completion, but the handle returned by the firmware mapped to no current command. The frequency of this problem is low under such a load- it would usually take an 30 minutes per 'lost' interrupt. I doubled the timeout for commands to see if it just was an edge case of waiting too short a period. This has no effect. I gathered and printed out microtimes for the watchdog completed command and the completion that couldn't find a command- it was always the case that the order of occurrence was "timeout, completion" separated by a time on the order of 100 to 150 ms. This caused me to consider 'firmware constipation' as to be a possible culprit. That is, resubmission of a command to the device that had suffered a watchdog timeout seemed to cause the presumed dead command to show back up. I added code in the watchdog routine that, when first entered for the command, marks the command with a flag, reissues a local timeout call for one second later, but also then issues a MARKER Request Queue entry to the Qlogic f/w. A MARKER entry is used typically after a Bus Reset to cause the f/w to get synchronized with respect to either a Bus, a Nexus or a Target. Since I've added this code, I always now see the occasional watchdog timeout, but the command that was about to be terminated always now seems to be completed after the MARKER entry is issued (and before the timeout extension fires, which would come back and *really* terminate the command). |
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| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| kerberosIV | ||
| lib | ||
| libexec | ||
| release | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.upgrade | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel and the contents of /etc. Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel with config(8) is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/handbook/kernelconfig.html And in the config(8) man page. The sample kernel configuration files reside in the sys/i386/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file LINT contains entries for all possible devices, not just those commonly used, and is meant more as a general reference than an actual kernel configuration file (a kernel built from it wouldn't even run). Source Roadmap: --------------- bin System/User commands. contrib Packages contributed by 3rd parties. crypto Export controlled stuff (see crypto/README). etc Template files for /etc games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberosIV Kerberos package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure DES and DES-related utilities - NOT FOR EXPORT! share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/handbook/synching.html