[LinuxBIOS] Proposed change to amd/amdk8/incoherent_ht.c

[San Mehat]

While we're on the 'error handling' track, I also had an issue where
'ht_optimize_link()' was continually indicating that a reset was required
and causing an endless reset loop. The culprit was the code which performs
an 8 bit read to get the *current* frequency of the link and doesn't mask
off the error bits next to the frequency bits (bits 0-4 are frequency, and
bits 5-7 are error status).

Once again, this was triggered by a transient error on the link (likely due
to link retraining).

Heres the patch:

****START CUT****
Index: incoherent_ht.c
===================================================================
--- incoherent_ht.c (revision 2064)
+++ incoherent_ht.c (working copy)

@@ -198,12 +206,12 @@
freq = log2(freq_cap1 & freq_cap2);

/* See if I am changing the link freqency */
- old_freq = pci_read_config8(dev1, pos1 + LINK_FREQ(offs1));
+ old_freq = (pci_read_config8(dev1, pos1 + LINK_FREQ(offs1)) & 0x0f); //
Mask off error bits
needs_reset |= old_freq != freq;
- old_freq = pci_read_config8(dev2, pos2 + LINK_FREQ(offs2));
+ old_freq = (pci_read_config8(dev2, pos2 + LINK_FREQ(offs2)) & 0x0f); //
Mask off error bits
needs_reset |= old_freq != freq;

- /* Set the Calulcated link frequency */
+ /* Set the Calculated link frequency */
pci_write_config8(dev1, pos1 + LINK_FREQ(offs1), freq);
pci_write_config8(dev2, pos2 + LINK_FREQ(offs2), freq);
***END CUT****

San Mehat  writes:
> While we're on the 'error handling' track, I also had an issue where
> 'ht_optimize_link()' was continually indicating that a reset was required and
> causing an endless reset loop. The culprit was the code which performs an 8 bit
> read to get the *current* frequency of the link and doesn't mask off the error
> bits next to the frequency bits (bits 0-4 are frequency, and bits 5-7 are error
> status).
>
> Once again, this was triggered by a transient error on the link (likely due to
> link retraining).

Thanks.  We just committed an equivalent version. :)

Eric

[San Mehat]

fantastic ;)

On 10/26/05, Eric W. Biederman  wrote:
> San Mehat  writes:
> > While we're on the 'error handling' track, I also had an issue where
> > 'ht_optimize_link()' was continually indicating that a reset was
>
> required and
> > causing an endless reset loop. The culprit was the code which performs
>
> an 8 bit
> > read to get the *current* frequency of the link and doesn't mask off the
>
> error
> > bits next to the frequency bits (bits 0-4 are frequency, and bits 5-7
>
> are error
> > status).
> >
> > Once again, this was triggered by a transient error on the link (likely
>
> due to
> > link retraining).
>
> Thanks.  We just committed an equivalent version. :)
>
> Eric