On Thu, 10 Mar 2011 14:02:12 +0100, Takashi Iwai tiwai@suse.de wrote:
This reverts commit 951f3512dba5bd44cda3e5ee22b4b522e4bb09fb
drm/i915: Do not handle backlight combination mode speciallysince this commit introduced other regressions due to untouched LBPC register, e.g. the backlight dimmed after resume.
In addition to the revert, this patch includes a fix for the original issue (weird backlight levels) by removing the wrong bit shift for computing the current backlight level. Also, including typo fixes (lpbc -> lbpc).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34524 Acked-by: Indan Zupancic indan@nul.nu Cc: stable@kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de
This looks good, and ensures that LBPC ranges from 0 - 0xfe as required.
The one thing we want is a comment that explains
val &= ~1;
The reason for this is that some ancient platforms wire this bit to be "go to max backlight", or at least that's why this was in the 2D driver from which this code was derived.
Reviewed-by: Keith Packard keithp@keithp.com Reviewed-by: Jesse Barnes jbarnes@virtuousgeek.org