From: Thomas Zimmermann <tzimmermann@suse.de>
To: Javier Martinez Canillas <javierm@redhat.com>,
Robin Murphy <robin.murphy@arm.com>,
liviu.dudau@arm.com
Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] drm/arm/hdlcd: Take over EFI framebuffer properly
Date: Wed, 15 Jun 2022 09:53:18 +0200 [thread overview]
Message-ID: <0b6426ec-b436-29b4-43d8-cf6449b3a202@suse.de> (raw)
In-Reply-To: <a8350570-0ed5-dc91-c4a4-76931dec0c1d@redhat.com>
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Am 15.06.22 um 09:50 schrieb Javier Martinez Canillas:
[...]
>> Historically, most drivers call this function very early. But for error
>> recovery it would be better to do it as late as possible. Ideally,
>> drivers would first initialize their DRM software state, then kickout
>> the generic driver, and finally take over hardware. But that would
>> require a careful review of each driver. :/
>>
>
> We got bug reports on Fedora about regressions caused by the fact that some
> programs made the (wrong) assumption that /dev/dri/card0 would be the "main"
> display and just hard-coded that path.
Shh! Don't tell anyone.
>
> But removing the conflicting framebuffers after calling devm_drm_dev_alloc()
> breaks this assumption, since the registered device will be /dev/dri/card1.
>
> All this is to say that doing it too late, even if nothing is touching the HW
> yet, could still have unexpected consequences across your graphics stack.
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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next prev parent reply other threads:[~2022-06-15 7:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 13:04 [PATCH] drm/arm/hdlcd: Take over EFI framebuffer properly Robin Murphy
2022-06-14 13:26 ` Javier Martinez Canillas
2022-06-14 13:36 ` Robin Murphy
2022-06-14 13:48 ` Thomas Zimmermann
2022-06-14 21:06 ` Robin Murphy
2022-06-15 7:39 ` Thomas Zimmermann
2022-06-15 7:50 ` Javier Martinez Canillas
2022-06-15 7:53 ` Thomas Zimmermann [this message]
2022-06-15 8:00 ` Javier Martinez Canillas
2022-06-15 10:26 ` Liviu Dudau
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