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Fri, 11 Jul 2025 01:56:43 -0700 (PDT) Date: Fri, 11 Jul 2025 10:56:41 +0200 From: Simona Vetter To: Rodrigo Vivi Cc: Raag Jadav , Christian =?iso-8859-1?Q?K=F6nig?= , Simona Vetter , Riana Tauro , intel-xe@lists.freedesktop.org, anshuman.gupta@intel.com, lucas.demarchi@intel.com, aravind.iddamsetty@linux.intel.com, umesh.nerlige.ramappa@intel.com, frank.scarbrough@intel.com, sk.anirban@intel.com, =?iso-8859-1?Q?Andr=E9?= Almeida , David Airlie , dri-devel@lists.freedesktop.org Subject: Re: [PATCH v4 1/9] drm: Add a vendor-specific recovery method to device wedged uevent Message-ID: References: <20250709112024.1053710-1-riana.tauro@intel.com> <20250709112024.1053710-2-riana.tauro@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Operating-System: Linux phenom 6.12.30-amd64 X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Thu, Jul 10, 2025 at 03:00:06PM -0400, Rodrigo Vivi wrote: > On Thu, Jul 10, 2025 at 01:24:52PM +0300, Raag Jadav wrote: > > On Thu, Jul 10, 2025 at 11:37:14AM +0200, Christian König wrote: > > > On 10.07.25 11:01, Simona Vetter wrote: > > > > On Wed, Jul 09, 2025 at 12:52:05PM -0400, Rodrigo Vivi wrote: > > > >> On Wed, Jul 09, 2025 at 05:18:54PM +0300, Raag Jadav wrote: > > > >>> On Wed, Jul 09, 2025 at 04:09:20PM +0200, Christian König wrote: > > > >>>> On 09.07.25 15:41, Simona Vetter wrote: > > > >>>>> On Wed, Jul 09, 2025 at 04:50:13PM +0530, Riana Tauro wrote: > > > >>>>>> Certain errors can cause the device to be wedged and may > > > >>>>>> require a vendor specific recovery method to restore normal > > > >>>>>> operation. > > > >>>>>> > > > >>>>>> Add a recovery method 'WEDGED=vendor-specific' for such errors. Vendors > > > >>>>>> must provide additional recovery documentation if this method > > > >>>>>> is used. > > > >>>>>> > > > >>>>>> v2: fix documentation (Raag) > > > >>>>>> > > > >>>>>> Cc: André Almeida > > > >>>>>> Cc: Christian König > > > >>>>>> Cc: David Airlie > > > >>>>>> Cc: > > > >>>>>> Suggested-by: Raag Jadav > > > >>>>>> Signed-off-by: Riana Tauro > > > >>>>> > > > >>>>> I'm not really understanding what this is useful for, maybe concrete > > > >>>>> example in the form of driver code that uses this, and some tool or > > > >>>>> documentation steps that should be taken for recovery? > > > >> > > > >> The case here is when FW underneath identified something badly corrupted on > > > >> FW land and decided that only a firmware-flashing could solve the day and > > > >> raise interrupt to the driver. At that point we want to wedge, but immediately > > > >> hint the admin the recommended action. > > > >> > > > >>>> > > > >>>> The recovery method for this particular case is to flash in a new firmware. > > > >>>> > > > >>>>> The issues I'm seeing here is that eventually we'll get different > > > >>>>> vendor-specific recovery steps, and maybe even on the same device, and > > > >>>>> that leads us to an enumeration issue. Since it's just a string and an > > > >>>>> enum I think it'd be better to just allocate a new one every time there's > > > >>>>> a new strange recovery method instead of this opaque approach. > > > >>>> > > > >>>> That is exactly the opposite of what we discussed so far. > > > > > > > > Sorry, I missed that context. > > > > > > > >>>> The original idea was to add a firmware-flush recovery method which > > > >>>> looked a bit wage since it didn't give any information on what to do > > > >>>> exactly. > > > >>>> > > > >>>> That's why I suggested to add a more generic vendor-specific event > > > >>>> with refers to the documentation and system log to see what actually > > > >>>> needs to be done. > > > >>>> > > > >>>> Otherwise we would end up with events like firmware-flash, update FW > > > >>>> image A, update FW image B, FW version mismatch etc.... > > > > > > > > Yeah, that's kinda what I expect to happen, and we have enough numbers for > > > > this all to not be an issue. > > > > > > > >>> Agree. Any newly allocated method that is specific to a vendor is going to > > > >>> be opaque anyway, since it can't be generic for all drivers. This just helps > > > >>> reduce the noise in DRM core. > > > >>> > > > >>> And yes, there could be different vendor-specific cases for the same driver > > > >>> and the driver should be able to provide the means to distinguish between > > > >>> them. > > > >> > > > >> Sim, what's your take on this then? > > > >> > > > >> Should we get back to the original idea of firmware-flash? > > > > > > > > Maybe intel-firmware-flash or something, meaning prefix with the vendor? > > > > > > > > The reason I think it should be specific is because I'm assuming you want > > > > to script this. And if you have a big fleet with different vendors, then > > > > "vendor-specific" doesn't tell you enough. But if it's something like > > > > $vendor-$magic_step then it does become scriptable, and we do have have a > > > > place to put some documentation on what you should do instead. > > > > > > > > If the point of this interface isn't that it's scriptable, then I'm not > > > > sure why it needs to be an uevent? > > > > > > You should probably read up on the previous discussion, cause that is exactly what I asked as well :) > > > > > > And no, it should *not* be scripted. That would be a bit brave for a firmware update where you should absolutely not power down the system for example. > > I also don't like the idea or even the thought of scripting something like > a firmware-flash. But only to fail with a better pin point to make admin > lives easier with a notification. > > > > > > > In my understanding the new value "vendor-specific" basically means it is a known issue with a documented solution, while "unknown" means the driver has no idea how to solve it. > > Exactly, the hardware and firmware are giving the indication of what should be > done. It is not 'unknown'. > > > > > Yes, and since the recovery procedure is defined and known to the consumer, > > it can potentially be automated (atleast for non-firmware cases). > > > > > > I guess if you all want to stick with vendor-specific then I think that's > > Well, I would honestly prefer a direct firmware-flash, but if that is not > usable by other vendors and there's a push back on that, let's go with > the vendor-specific then. > > > > > ok with me too, but the docs should at least explain how to figure out > > > > from the uevent which vendor you're on with a small example. What I'm > > > > worried is that if we have this on multiple drivers userspace will > > > > otherwise make a complete mess and might want to run the wrong recovery > > > > steps. > > > > The device id along with driver can be identified from uevent (probably > > available inside DEVPATH somewhere) to distinguish the vendor. So the consumer > > already knows if the device fits the criteria for recovery. > > > > > > I think ideally, no matter what, we'd have a concrete driver patch which > > > > then also comes with the documentation for what exactly you're supposed to > > > > do as something you can script. And not just this stand-alone patch here. > > > > Perhaps the rest of the series didn't make it to dri-devel, which will answer > > most of the above. > > Riana, could you please try to provide a bit more documentation like Sima > asked and re-send the entire series to dri-devel? Yeah all the stuff discussed here needs to be included in the commit message. Also ideally the patch series would add a user in xe, and the xe patch would then also include documentation on how that firmware flash should happen. Also I guess the xe patch I guess should explain how backwards compatibility should work if there's ever a need for yet-another recovery method. Asking userspace to filter on specific pciid sounds brittle, I think worst case we'll just add vendor-specific-1 or something :-) Which is why I still think we should just enum them all, but I'm ok with just properly documenting the reasoning behind this all. Cheers, Sima > > Thanks, > Rodrigo. > > > > > Raag > > > > > >>>>>> --- > > > >>>>>> Documentation/gpu/drm-uapi.rst | 9 +++++---- > > > >>>>>> drivers/gpu/drm/drm_drv.c | 2 ++ > > > >>>>>> include/drm/drm_device.h | 4 ++++ > > > >>>>>> 3 files changed, 11 insertions(+), 4 deletions(-) > > > >>>>>> > > > >>>>>> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst > > > >>>>>> index 263e5a97c080..c33070bdb347 100644 > > > >>>>>> --- a/Documentation/gpu/drm-uapi.rst > > > >>>>>> +++ b/Documentation/gpu/drm-uapi.rst > > > >>>>>> @@ -421,10 +421,10 @@ Recovery > > > >>>>>> Current implementation defines three recovery methods, out of which, drivers > > > >>>>>> can use any one, multiple or none. Method(s) of choice will be sent in the > > > >>>>>> uevent environment as ``WEDGED=[,..,]`` in order of less to > > > >>>>>> -more side-effects. If driver is unsure about recovery or method is unknown > > > >>>>>> -(like soft/hard system reboot, firmware flashing, physical device replacement > > > >>>>>> -or any other procedure which can't be attempted on the fly), ``WEDGED=unknown`` > > > >>>>>> -will be sent instead. > > > >>>>>> +more side-effects. If recovery method is specific to vendor > > > >>>>>> +``WEDGED=vendor-specific`` will be sent and userspace should refer to vendor > > > >>>>>> +specific documentation for further recovery steps. If driver is unsure about > > > >>>>>> +recovery or method is unknown, ``WEDGED=unknown`` will be sent instead > > > >>>>>> > > > >>>>>> Userspace consumers can parse this event and attempt recovery as per the > > > >>>>>> following expectations. > > > >>>>>> @@ -435,6 +435,7 @@ following expectations. > > > >>>>>> none optional telemetry collection > > > >>>>>> rebind unbind + bind driver > > > >>>>>> bus-reset unbind + bus reset/re-enumeration + bind > > > >>>>>> + vendor-specific vendor specific recovery method > > > >>>>>> unknown consumer policy > > > >>>>>> =============== ======================================== > > > >>>>>> > > > >>>>>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > > > >>>>>> index cdd591b11488..0ac723a46a91 100644 > > > >>>>>> --- a/drivers/gpu/drm/drm_drv.c > > > >>>>>> +++ b/drivers/gpu/drm/drm_drv.c > > > >>>>>> @@ -532,6 +532,8 @@ static const char *drm_get_wedge_recovery(unsigned int opt) > > > >>>>>> return "rebind"; > > > >>>>>> case DRM_WEDGE_RECOVERY_BUS_RESET: > > > >>>>>> return "bus-reset"; > > > >>>>>> + case DRM_WEDGE_RECOVERY_VENDOR: > > > >>>>>> + return "vendor-specific"; > > > >>>>>> default: > > > >>>>>> return NULL; > > > >>>>>> } > > > >>>>>> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h > > > >>>>>> index 08b3b2467c4c..08a087f149ff 100644 > > > >>>>>> --- a/include/drm/drm_device.h > > > >>>>>> +++ b/include/drm/drm_device.h > > > >>>>>> @@ -26,10 +26,14 @@ struct pci_controller; > > > >>>>>> * Recovery methods for wedged device in order of less to more side-effects. > > > >>>>>> * To be used with drm_dev_wedged_event() as recovery @method. Callers can > > > >>>>>> * use any one, multiple (or'd) or none depending on their needs. > > > >>>>>> + * > > > >>>>>> + * Refer to "Device Wedging" chapter in Documentation/gpu/drm-uapi.rst for more > > > >>>>>> + * details. > > > >>>>>> */ > > > >>>>>> #define DRM_WEDGE_RECOVERY_NONE BIT(0) /* optional telemetry collection */ > > > >>>>>> #define DRM_WEDGE_RECOVERY_REBIND BIT(1) /* unbind + bind driver */ > > > >>>>>> #define DRM_WEDGE_RECOVERY_BUS_RESET BIT(2) /* unbind + reset bus device + bind */ > > > >>>>>> +#define DRM_WEDGE_RECOVERY_VENDOR BIT(3) /* vendor specific recovery method */ > > > >>>>>> > > > >>>>>> /** > > > >>>>>> * struct drm_wedge_task_info - information about the guilty task of a wedge dev > > > >>>>>> -- > > > >>>>>> 2.47.1 > > > >>>>>> > > > >>>>> > > > >>>> > > > > > > > -- Simona Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch