On Tue, Sep 10, 2024 at 06:53:19PM GMT, Raag Jadav wrote:
On Mon, Sep 09, 2024 at 03:01:50PM -0500, Lucas De Marchi wrote:On Sun, Sep 08, 2024 at 11:08:39PM GMT, Asahi Lina wrote: > On 9/8/24 12:07 AM, Lucas De Marchi wrote: > > On Sat, Sep 07, 2024 at 08:38:30PM GMT, Asahi Lina wrote: > > > On 9/6/24 6:42 PM, Raag Jadav wrote: > > > > Introduce device wedged event, which will notify userspace of wedged > > > > (hanged/unusable) state of the DRM device through a uevent. This is > > > > useful especially in cases where the device is in unrecoverable state > > > > and requires userspace intervention for recovery. > > > > > > > > Purpose of this implementation is to be vendor agnostic. Userspace > > > > consumers (sysadmin) can define udev rules to parse this event and > > > > take respective action to recover the device. > > > > > > > > Consumer expectations: > > > > ---------------------- > > > > 1) Unbind driver > > > > 2) Reset bus device > > > > 3) Re-bind driver > > > > > > Is this supposed to be normative? For drm/asahi we have a "wedged" > > > concept (firmware crashed), but the only possible recovery action is a > > > full system reboot (which might still be desirable to allow userspace to > > > trigger automatically in some scenarios) since there is no bus-level > > > reset and no firmware reload possible. > > > > maybe let drivers hint possible/supported recovery mechanisms and then > > sysadmin chooses what to do? > > How would we do this? A textual value for the event or something like > that? ("WEDGED=bus-reset" vs "WEDGED=reboot"?) If there's a need for more than one, than I think exposing the supported ones sorted by "side effect" in sysfs would be good. Something like: $ cat /sys/class/drm/card0/device/wedge_recover rebind bus-reset rebootHow do we expect the drivers to flag supported ones? Extra hooks?
The comment above... wedge_recover would be a sysfs exposed by the driver to userspace with the supported mechanisms. WEDGED=<mechanism> (which is also crafted by the driver or with explicit functions in drm) would report to userspace the minimum needed mechanism for recovery. Lucas De Marchi
