From: Thomas Zimmermann <tzimmermann@suse.de>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>,
linux-fbdev@vger.kernel.org, geert+renesas@glider.be,
corbet@lwn.net, daniel.vetter@ffwll.ch,
linux-doc@vger.kernel.org, bernie@plugable.com,
dri-devel@lists.freedesktop.org, sam@ravnborg.org
Subject: Re: [PATCH] fbdev: Remove udlfb driver
Date: Wed, 2 Dec 2020 09:01:58 +0100 [thread overview]
Message-ID: <d3dbe8bf-d5a3-dc6e-b98a-778d942ee7fa@suse.de> (raw)
In-Reply-To: <9e7cad29-a9c0-2e02-04a9-3149d7e15838@suse.de>
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Am 02.12.20 um 08:55 schrieb Thomas Zimmermann:
> Hi
>
> Am 01.12.20 um 12:20 schrieb Mikulas Patocka:
>>
>>
>> On Tue, 1 Dec 2020, Thomas Zimmermann wrote:
>>
>>> Hi
>>>
>>> Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
>>>>
>>>>
>>>> On Mon, 30 Nov 2020, Daniel Vetter wrote:
>>>>
>>>>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
>>>>>>
>>>>>> The framebuffer driver supports programs running full-screen
>>>>>> directly on
>>>>>> the framebuffer console, such as web browser "links -g", image viewer
>>>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
>>>>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
>>>>>
>>>>> Hm this should in general work on drm drivers. Without that it's
>>>>> clear the
>>>>> switch-over isn't really ready yet.
>>>>
>>>> I fixed it with this patch two years ago:
>>>> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
>>>>
>>>> But the patch never went through and the fb_defio feature was
>>>> removed in
>>>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
>>>>
>>>>
>>>> Without fb_defio, the only other possibility how to update the
>>>> screen is
>>>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master
>>>> mode, so
>>>> user programs like "links -g" can't issue it.
>>>
>>> That's confusing. DIRTYFB is only for DRM.
>>
>> Yes, you're right.
>>
>>> And why can links not run as DRM master mode? If it renders to the
>>> terminal,
>>> it should act like a composer. In that case it almost certainly wants
>>> master
>>> status.
>>>
>>> Best regards
>>> Thomas
>>
>> How can a userspace program acquire master mode without being suid?
>
> For my understanding, there's no easy solution to that. :/
>
> I guess we (DRM devs) have to treat fbdev as the solution for use cases
> such as ours.
s/ours/yours
>
> For the unplug issue, I'll try to reproduce and fix it.
>
> For the performance problems, we might be able to squeeze a few more
> cycles out of it.
>
> Best regards
> Thomas
>
>>
>> Is there some "Hello World!" program that shows how to use DRM? I'm
>> not an
>> expert in DRM, but if there were some tutorial+documentation, I could
>> consider porting "links" to it.
>>
>> Mikulas
>>
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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next prev parent reply other threads:[~2020-12-02 8:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 12:52 [PATCH] fbdev: Remove udlfb driver Thomas Zimmermann
2020-11-30 14:31 ` Mikulas Patocka
2020-11-30 15:41 ` Daniel Vetter
2020-11-30 18:39 ` Mikulas Patocka
2020-11-30 21:06 ` Daniel Vetter
2020-12-01 11:26 ` Mikulas Patocka
2020-12-01 8:07 ` Thomas Zimmermann
2020-12-01 11:20 ` Mikulas Patocka
2020-12-02 7:55 ` Thomas Zimmermann
2020-12-02 8:01 ` Thomas Zimmermann [this message]
2020-12-02 8:29 ` Pekka Paalanen
2020-12-02 17:52 ` Daniel Vetter
2020-12-01 8:02 ` Thomas Zimmermann
2020-12-01 10:44 ` Mikulas Patocka
2020-12-01 20:09 ` Mikulas Patocka
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