Re: [PATCH v3 1/2] drm: introduce KMS recovery mechanism

[Michel Dänzer]

On 2/18/26 10:22, Michel Dänzer wrote:
> On 2/18/26 01:45, Hamza Mahfooz wrote:
>> On Mon, Feb 16, 2026 at 10:28:13AM +0100, Michel Dänzer wrote:
>>> On 2/14/26 23:16, Hamza Mahfooz wrote:
>>>> On Sat, Feb 14, 2026 at 03:02:49PM +0100, Michel Dänzer wrote:
>>>>
>>>>> In principle it's possible to do (the equivalent of) a modeset with the current state for all CRTCs, no need to do it separately per CRTC.
>>>>
>>>> AFAIK that is what the uevent is already doing (unless I'm mistaken).
>>>
>>> This is about just doing a full modeset, which isn't something user space can do in response to a wedged event.
>>
>> I was referring to what compositors are doing in response to
>> `drm_kms_helper_hotplug_event()`. Perhaps, the enum constants should be
>> renamed, since the forced modeset is actually sent when the current
>> reset phase is DRM_KMS_RESET_NONE (the phase is updated before sending
>> out the event though).
> 
> Ah, you're talking about the drm_kms_helper_hotplug_event call in drm_atomic_helper_wait_for_flip_done (I thought "uevent" referred to drm_dev_wedged_event in patch 2).
> 
> I don't know about other compositors, but I don't think mutter will do a modeset in response to a hotplug event if no KMS state changed (because some monitors can generate spurious hotplug events).

FWIW, if it really turns out impossible for the kernel to do a modeset itself (which I remain unconvinced of), one way to require a modeset from user space is to set the "link-status" connector property to "Bad".


-- 
Earthling Michel Dänzer       \        GNOME / Xwayland / Mesa developer
https://redhat.com             \               Libre software enthusiast