Re: [PATCH v2 1/5] drm: Add a firmware flash method to device wedged uevent

[Raag Jadav <raag.jadav@intel.com>]

On Tue, Jul 01, 2025 at 05:11:24PM +0530, Riana Tauro wrote:
> On 7/1/2025 5:07 PM, Riana Tauro wrote:
> > On 6/30/2025 11:03 PM, Rodrigo Vivi wrote:
> > > On Mon, Jun 30, 2025 at 10:29:10AM +0200, Christian König wrote:
> > > > On 27.06.25 23:38, Rodrigo Vivi wrote:
> > > > > > > Or at least print a big warning into the system log?
> > > > > > > 
> > > > > > > I mean a firmware update is usually something which
> > > > > > > the system administrator triggers very explicitly
> > > > > > > because when it fails for some reason (e.g.
> > > > > > > unexpected reset, power outage or whatever) it can
> > > > > > > sometimes brick the HW.
> > > > > > > 
> > > > > > > I think it's rather brave to do this automatically.
> > > > > > > Are you sure we don't talk past each other on the
> > > > > > > meaning of the wedge event?
> > > > > > 
> > > > > > The goal is not to do that automatically, but raise the
> > > > > > uevent to the admin
> > > > > > with enough information that they can decide for the right correctable
> > > > > > action.
> > > > > 
> > > > > Christian, Andre, any concerns with this still?
> > > > 
> > > > Well, that sounds not quite the correct use case for wedge events.
> > > > 
> > > > See the wedge event is made for automation.
> > > 
> > > I respectfully disagree with this statement.
> > > 
> > > The wedged state in i915 and xe, then ported to drm, was never just about
> > > automation. Of course, the unbind + flr + rebind is one that driver
> > > cannot
> > > do by itself, hence needs automation. But wedge cases were also very
> > > useful
> > > in other situations like keeping the device in the failure stage for
> > > debuging
> > > (without automation) or keeping other critical things up like
> > > display with SW
> > > rendering (again, nothing about automation).
> > > 
> > > > For example to allow a process supervising containers get the
> > > > device working again and re-start the container which used it or
> > > > gather crash log etc .....
> > > > 
> > > > When you want to notify the system administrator which manual
> > > > intervention is necessary then I would just write that into the
> > > > system log and raise a device event with WEDGED=unknown.
> > > > 
> > > > What we could potentially do is to separate between
> > > > WEDGED=unknown and WEDGED=manual, e.g. between driver has no
> > > > idea what to do and driver printed useful info into the system
> > > > log.
> > > 
> > > Well, you are right here. Even our official documentation in drm-uapi.rst
> > > already tells that firmware flashing should be a case for 'unknown'.
> > 
> > I had added specific method since we know firmware flash will recover
> > the error.  Sure will change it.
> > 
> > In the current code, there is no recovery method named "unknown" even
> > though the document mentions it
> > 
> > https://elixir.bootlin.com/linux/v6.16-rc4/source/drivers/gpu/drm/
> > drm_drv.c#L534
> > 
> > Since we are adding something new, can it be "manual" instead of unknown?
> 
> Okay missed it. It's in the drm_dev_wedged_event function. Will use unknown
> > 
> > > Let's go with that then. And use other hints like logs and sysfs so,
> > > Admin
> > > has a better information of what to do.
> > > 
> > > > But creating an event with WEDGED=firmware-flash just sounds to
> > > > specific, when we go down that route we might soon have
> > > > WEDGE=change- bios-setting, WEDGE=....
> > > 
> > > Well, I agree that we shouldn't explode the options exponentially here.
> > > 
> > > Although I believe that firmware flashing should be a common case in many
> > > case and could be a candidate for another indication.
> > > 
> > > But let's move on with WEDGE='unknown' for this case.

I understand that WEDGED=firmware-flash can't be handled in a generic way
for all drivers but it is simply not as same as WEDGED=unknown since the
driver knows something specific needs to be done here.

I'm wondering if we could add a WEDGED=vendor-specific method for such
cases?

Chris? André?

Raag