Patch "fbdev/efifb: Fix 16 color palette entry calculation" has been added to the 4.4-stable tree

Patch "fbdev/efifb: Fix 16 color palette entry calculation" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fbdev/efifb: Fix 16 color palette entry calculation

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fbdev-efifb-fix-16-color-palette-entry-calculation.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d50b3f43db739f03fcf8c0a00664b3d2fed0496e Mon Sep 17 00:00:00 2001
From: Max Staudt <mstaudt@suse.de>
Date: Mon, 13 Jun 2016 19:15:59 +0200
Subject: fbdev/efifb: Fix 16 color palette entry calculation

From: Max Staudt <mstaudt@suse.de>

commit d50b3f43db739f03fcf8c0a00664b3d2fed0496e upstream.

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@suse.de>
Acked-By: Peter Jones <pjones@redhat.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/video/fbdev/efifb.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -52,9 +52,9 @@ static int efifb_setcolreg(unsigned regn
 		return 1;
 
 	if (regno < 16) {
-		red   >>= 8;
-		green >>= 8;
-		blue  >>= 8;
+		red   >>= 16 - info->var.red.length;
+		green >>= 16 - info->var.green.length;
+		blue  >>= 16 - info->var.blue.length;
 		((u32 *)(info->pseudo_palette))[regno] =
 			(red   << info->var.red.offset)   |
 			(green << info->var.green.offset) |


Patches currently in stable-queue which might be from mstaudt@suse.de are

queue-4.4/fbdev-efifb-fix-16-color-palette-entry-calculation.patch