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Further adjust the workaround in r234501. Rounding all small requests up

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to 32k swamped the controller causing firmware hangs.  Instead, round
requests smaller than 64k up to the next power of 2 as a general rule.
To handle the one known special case of a command that accepts a 12k
buffer returning a 24k-ish reply, round requests between 8k and 16k up
to 32k rather than 16k.  The result is that commands less than 8k should
now be rounded up to a smaller size (either 4k or 8k) rather than 32k.

PR:		kern/155658
Tested by:	Andreas Longwitz
MFC after:	1 week
This commit is contained in:
John Baldwin 2012-10-05 15:52:31 +00:00
parent 102548d143
commit f8d6c20a0f
1 changed files with 8 additions and 2 deletions
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10
sys/dev/amr/amr.c
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@ -533,13 +533,19 @@ shutdown_out:
* The amr(4) firmware relies on this feature. In fact, it assumes
* the buffer is always a power of 2 up to a max of 64k. There is
* also at least one case where it assumes a buffer less than 16k is
* greater than 16k. Force a minimum buffer size of 32k and round
* sizes between 32k and 64k up to 64k as a workaround.
* greater than 16k. However, forcing all buffers to a size of 32k
* causes stalls in the firmware. Force each command smaller than
* 64k up to the next power of two except that commands between 8k
* and 16k are rounded up to 32k instead of 16k.
*/
static unsigned long
amr_ioctl_buffer_length(unsigned long len)
{
if (len <= 4 * 1024)
return (4 * 1024);
if (len <= 8 * 1024)
return (8 * 1024);
if (len <= 32 * 1024)
return (32 * 1024);
if (len <= 64 * 1024)