linux-kernel - Re: [PATCH v4 0/3] console/fbcon: Add support for deferred console takeover

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Message-id: <66532157.tkLS2buF0U@amdc3058>
Date:   Wed, 27 Jun 2018 11:47:51 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Daniel Vetter <daniel@...ll.ch>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linux-fbdev@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/3] console/fbcon: Add support for deferred console
 takeover

On Wednesday, June 27, 2018 11:15:20 AM Daniel Vetter wrote:
> On Tue, Jun 26, 2018 at 08:36:09PM +0200, Hans de Goede wrote:
> > Hi All,
> > 
> > Here is v4 of my patch-set, to delay fbcon taking over the console (and
> > binding to fbdev devices) until there actually is some text output to the
> > console. This is intended for use with the "quiet" cmdline option, in
> > combination with a bootloader which leaves the vendor's logo /
> > EFI bootgraphics put up by the firmware intact on the EFI framebuffer.
> > 
> > The end goal here is a boot where the firmware shows its boot graphics
> > and these stay in place for a couple of seconds until the GUI loads and
> > the GUI then smoothly takes over the framebuffer without any distruptions.
> > 
> > This patch-set spans 2 subsystems.
> > 
> > Petr, the printk subsys change is really trivial (1 line addition) can we
> > get your Acked-by for merging all 3 patches through the fbdev tree?
> > 
> > Changelog:
> > 
> > Changes in v4:
> > -Keep the comments about which fbcon functions need locks in place
> > 
> > Changes in v3:
> > -Export is_console_locke() for use in modules (as fbcon may be built as a .ko)
> > -Use WARN_CONSOLE_UNLOCKED() in several places in the fbcon code to assert
> >  proper locking (requested by Daniel)
> > -Unregister the fbcon-dummycon-output-notifier on fbcon_exit() (req. by Daniel)
> > -Document the fbcon=nodefer commandline option (req. by Emil)
> > 
> > Changes in v2:
> > -Check the whole string when checking for erases in putcs, instead of just
> >  the first char
> > -Make dummycon_blank return 1, so that a redraw gets triggered and any text
> >  rendered while blanked gets output so that it can trigger a deferred
> >  takeover if one is pending
> 
> Wrt merging I think it'd be best if we stuff this into drm-misc-next -
> that will increase testing by gpu drivers a lot, instead of a suprise when
> the fbdev pull lands in upstream.
> 
> Bart, is that ok with you?

Not really, since there are efifb changes in the queue which depend
on this series I would really prefer to merge all patches through
fbdev tree.

Also fbdev tree is pulled into -next kernels so testing coverage
should be okay (I assume that everybody are testing -next kernels in
addition to their own branches :-)..

> Hans, if Bart acks this you can directly push this imo.
> -Daniel

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics