lkml.org 
[lkml]   [2006]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] corruption during e100 MDI register access
"ODonnell, Michael" <Michael.ODonnell@stratus.com> wrote:
>
> We have identified two related bugs in the e100 driver and we request
> that they be repaired in the official Intel version of the driver.
>
> Both bugs are related to manipulation of the MDI control register.
>
> The first problem is that the Ready bit is being ignored when
> writing to the Control register; we noticed this because the Linux
> bonding driver would occasionally come to the spurious conclusion
> that the link was down when querying Link State. It turned out
> that by failing to wait for a previous command to complete it was
> selecting what was essentially a random register in the MDI register
> set. When we added code that waits for the Ready bit (as shown in
> the patch file below) all such problems ceased.
>
> The second problem is that, although access to the MDI registers
> involves multiple steps which must not be intermixed, nothing was
> defending against two or more threads attempting simultaneous access.
> The most obvious situation where such interference could occur
> involves the watchdog versus ioctl paths, but there are probably
> others, so we recommend the locking shown in our patch file.

Your patches are coming through wordwrapped. Please fix your email client
in future.

Please also prepare patches in `patch -p1' form.
http://www.zip.com.au/~akpm/linux/patches/stuff/tpp.txt may prove useful.

This patch potentially spins for four milliseconds with interrupts off,
which will be unpopular. Is there no alternative?

Anyway, I queued the patch in my kernel so the issue won't be forgotten
about. I also queued a patch which makes your patch comply with kernel
coding style - it wasn't very close at all.

Thanks.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-01-09 14:03    [W:0.051 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site