Re: [PATCH] fbcon: Fix vc attr at deinit

On Wed, 11 Jan 2017 15:50:43 +0100,
Bartlomiej Zolnierkiewicz wrote:

Hi,

On Tuesday, January 10, 2017 05:09:43 PM Bartlomiej Zolnierkiewicz wrote:

quoted

Hi,

On Tuesday, January 10, 2017 04:47:30 PM Takashi Iwai wrote:

quoted

On Thu, 05 Jan 2017 13:26:07 +0100,
Tomi Valkeinen wrote:

quoted

On 04/01/17 15:50, Takashi Iwai wrote:

quoted

On Tue, 03 Jan 2017 16:03:22 +0100,
Takashi Iwai wrote:

quoted

fbcon can deal with vc_hi_font_mask (the upper 256 chars) and adjust
the vc attrs dynamically when vc_hi_font_mask is changed at
fbcon_init().  When the vc_hi_font_mask is set, it remaps the attrs in
the existing console buffer with one bit shift up (for 9 bits), while
it remaps with one bit shift down (for 8 bits) when the value is
cleared.  It works fine as long as the font gets updated after fbcon
was initialized.

However, we hit a bizarre problem when the console is switched to
another fb driver (typically from vesafb or efifb to drmfb).  At
switching to the new fb driver, we temporarily rebind the console to
the dummy console, then rebind to the new driver.  During the
switching, we leave the modified attrs as is.  Thus, the new fbcon
takes over the old buffer as if it were to contain 8 bits chars
(although the attrs are still shifted for 9 bits), and effectively
this results in the yellow color texts instead of the original white
color, as found in the bugzilla entry below.

An easy fix for this is to re-adjust the attrs before leaving the
fbcon at con_deinit callback.  Since the code to adjust the attrs is
already present in the current fbcon code, in this patch, we simply
factor out the relevant code, and call it from fbcon_deinit().

Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id00619
Signed-off-by: Takashi Iwai <redacted>

Actually not only checkpatch but also I can't find the proper
maintainer for this...

Tomi, could you check and take if it's OK?

Ideally, this kind of stuff should have been in rather vt side, I
suppose.  But since the code is already present in fbcon, it's easier
to reuse it as a fix for now.

I'm not fbdev maintainer anymore. Added Bartlomiej (and Andrew).

Bartlomiej (or Andrew), could you check the patch?  In case you missed
it, I attach it below again.

Thanks, it is on TODO (should be processed till the end of the week).

Patch queued for 4.11, thanks.

Great, thanks!


Takashi