On 3/16/22 12:21 PM, Limonciello, Mario wrote:
[Public]
On 3/16/22 10:29 AM, Limonciello, Mario wrote:
[Public]
+ Alex D
Alex, just FYI this was something that came to an AMD bug tracker and
wanted you to be aware there are W/A going into nvidia-wmi-ec-backlight
for some firmware problems with the mux.
IIRC that was the original suspicion too on the bug reports.
Is this on a public or private bug tracker? If this was observed on
systems other than the one already added to these quirks, could you
share the details of the systems so they can be added as well? (Or I
suppose you may want to test to see if these WARs are effective on the
affected systems as well; we can always expand the quirks table later.)
We (AMD folks) don't have the affected systems, we were just trying to help
users and things pointed at this driver, which seems to have yielded a good
investigation and conclusion!
IIRC this is the bug you want linked in the commit message:
https://gitlab.freedesktop.org/drm/amd/-/issues/1671
Ah, thanks. Most of the people on this bug seem like their problem was
that they didn't have the nvidia-wmi-ec-backlight driver, which also
didn't exist at the time the bug was filed. There is one person with a
newer comment reporting behavior that sounds like what this patch works
around, and it is the same person who initially reported the issue to me. :)
But these two look possible to be the same root cause:
https://gitlab.freedesktop.org/drm/amd/-/issues/1791
This one sounds like it might be a different issue, since it was
apparently working at some point with a kernel that didn't have the EC
backlight driver, and then not working on a newer kernel that also
didn't have the EC backlight driver. That is, of course, assuming
vanilla kernels: it is certainly possible that the EC backlight driver
was backported.
https://gitlab.freedesktop.org/drm/amd/-/issues/1794
This sounds like it could possibly be a simple case of not having the EC
backlight driver. Notably, the backlight device exposed by the amdgpu
driver never works, in contrast to the system these workarounds are
targeting, where the amdgpu driver's backlight device initially works,
but then stops working after the first suspend/resume cycle (and the EC
backlight driver doesn't work initially, but then starts working after
suspend/resume).
If you end up introducing a module parameter to try to activate these quirks
it might be viable to ask the folks in those issues to try the v2 of your patch too
when you're ready with the module parameter.
v1 already has the quirks plumbed up to module parameters (those module
parameters just don't have corresponding sysfs entries). In any case, I
only see one report between those bugs that sounds like the issue these
WARs are meant to address, and since it's from the same reporter, it
sounds like we won't need to be adding any additional quirks table
entries right away.
Comments inline as well.
-----Original Message-----
From: Daniel Dadap <ddadap@xxxxxxxxxx>
Sent: Wednesday, March 16, 2022 10:11
To: Barnabás Pőcze <pobrn@xxxxxxxxxxxxxx>
Cc: platform-driver-x86@xxxxxxxxxxxxxxx; Alexandru Dinu
<alex.dinu07@xxxxxxxxx>; Hans de Goede <hdegoede@xxxxxxxxxx>;
markgross@xxxxxxxxxx
Subject: Re: [PATCH] nvidia-wmi-ec-backlight: Add workarounds for
confused firmware
[ ... ]
On 3/15/22 9:50 PM, Barnabás Pőcze wrote:
[ ... ]
Lastly, is it expected that these bugs will be properly fixed?
Possibly, but I wouldn't hold out hope for it for an issue at this scale
on an already shipping system.
This question I'm assuming was aimed at narrowing the quirk to only
match certain FW versions or so. If there is no certainty of when/if it
will be fixed I agree with current direction.
However I think it's still worth at least noting near the quirk in a comment
what firmware version it was identified. If later there is confirmation that
a particular firmware version had fixed it the quirk can be adjusted to be
dropped.
Thanks, Mario. Sure, I'll make sure the firmware version this was first
observed in is noted.
