linux-kernel - Re: [PATCH RESEND] fbdev/efifb: Fix 16 color palette entry calculation

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Date:	Wed, 10 Aug 2016 13:53:06 +0300
From:	Tomi Valkeinen <tomi.valkeinen@...com>
To:	Max Staudt <mstaudt@...e.de>, <pjones@...hat.com>,
	<plagnioj@...osoft.com>
CC:	<eich@...e.de>, <tiwai@...e.de>, <agraf@...e.de>,
	<linux-fbdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<matt@...eblueprint.co.uk>, <stable@...r.kernel.org>
Subject: Re: [PATCH RESEND] fbdev/efifb: Fix 16 color palette entry
 calculation



On 13/06/16 20:15, Max Staudt wrote:
> When using efifb with a 16-bit (5:6:5) visual, fbcon's text is rendered
> in the wrong colors - e.g. text gray (#aaaaaa) is rendered as green
> (#50bc50) and neighboring pixels have slightly different values
> (such as #50bc78).
> 
> The reason is that fbcon loads its 16 color palette through
> efifb_setcolreg(), which in turn calculates a 32-bit value to write
> into memory for each palette index.
> Until now, this code could only handle 8-bit visuals and didn't mask
> overlapping values when ORing them.
> 
> With this patch, fbcon displays the correct colors when a qemu VM is
> booted in 16-bit mode (in GRUB: "set gfxpayload=800x600x16").
> 
> Fixes: 7c83172b98e5 ("x86_64 EFI boot support: EFI frame buffer driver")  # v2.6.24+
> Signed-off-by: Max Staudt <mstaudt@...e.de>
> Acked-By: Peter Jones <pjones@...hat.com>
> Cc: stable@...r.kernel.org
> ---
>  drivers/video/fbdev/efifb.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

Thanks, queued for v4.9.

 Tomi




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