Re: [PATCH v2] host/rootfs: Don't wait for /dev/dri/card0

[Demi Marie Obenour <demiobenour@gmail.com>]

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On 6/24/26 04:55, Alyssa Ross wrote:
> Alyssa Ross <hi@alyssa.is> writes:
> 
>> Demi Marie Obenour <demiobenour@gmail.com> writes:
>>
>>> Weston can find a card itself.  If the card is not ready, it will exit,
>>> but s6 will automatically restart it.
>>>
>>> Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
>>
>> I don't think this commit message really captures it.  As long as the
>> card is not hotplugged, it _will_ be ready, as far as I know, because it
>> will become ready when DRM is loaded, before userspace starts.  This
>> makes it sound like Weston not finding a card and being restarted by s6
>> would be routine behaviour, whereas we'd actually not expect to ever see
>> it, except in the very unusual case of somebody having no cards at boot
>> and later hotplugging one.  (Even then it's not ideal to need to restart
>> in a loop, but that case can wait for COSMIC.)
>>
>> I suggest the following alternative, which also removes some other
>> obsolete instances of the same pattern.
>>
>> From 71216f0aa36049cbd3c7b7562e6e7ff225a1c810 Mon Sep 17 00:00:00 2001
>> From: Alyssa Ross <hi@alyssa.is>
>> Date: Tue, 26 May 2026 16:05:21 +0200
>> Subject: [PATCH] Stop waiting for /dev/dri/card0
>>
>> On the host, which does not run in a well-controlled VM environment,
>> there might not be a card0 (sometimes you just get card1).  This
>> causes hangs.  It hasn't been necessary to wait for non-hotplugged DRI
>> devices to exist since the Nixpkgs kernel set CONFIG_DRM=y.  (If
> 
> Alas this is not true upon further investigation.  I saw
> release/checks/wayland fail with this applied, because while DRM was
> loaded pre-userspace, DRM_BOCHS still wasn't.  s6 would indeed just
> restart Weston until it works, but I don't really want a restart loop to
> be a routine thing…

Is it okay to just let the restart loop happen until Spectrum switches
to COSMIC?  An alternative would be to use a udev rule and a FIFO,
but that's extra work that will be thrown away later.
-- 
Sincerely,
Demi Marie Obenour (she/her/hers)

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