linux-fbdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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>


[-- Attachment #1.1: Type: text/plain, Size: 2558 bytes --]



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


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d3dbe8bf-d5a3-dc6e-b98a-778d942ee7fa@suse.de \
    --to=tzimmermann@suse.de \
    --cc=bernie@plugable.com \
    --cc=corbet@lwn.net \
    --cc=daniel.vetter@ffwll.ch \
    --cc=daniel@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=geert+renesas@glider.be \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=mpatocka@redhat.com \
    --cc=sam@ravnborg.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).