On Mon, Mar 11, 2013 at 6:16 AM, Jani Nikula <jani.nikula at linux.intel.com> wrote: > Interesting snippets from your dmesgs: > > 1) good > > [ 0.000000] Linux version 3.6.0-rc6+ (chrisl at ideapad.lan) (gcc version 4.7.2 20121109 (Red Hat 4.7.2-8) (GCC) ) #25 SMP Wed Feb 20 12:55:06 PST 2013 > ... > [ 5.341431] [drm:intel_panel_get_max_backlight], max backlight PWM = 4648 > [ 5.341442] [drm:intel_panel_actually_set_backlight], set backlight PWM = 4648 > [ 5.342572] [drm:intel_panel_get_max_backlight], max backlight PWM = 4648 > [ 5.342578] [drm:intel_panel_actually_set_backlight], set backlight PWM = 4648 > > 2) bad > > [ 0.000000] Linux version 3.8.0-rc7+ (chrisl at ideapad.lan) (gcc version 4.7.2 20121109 (Red Hat 4.7.2-8) (GCC) ) #23 SMP Tue Feb 19 19:24:57 PST 2013 > ... > [ 5.692853] [drm:asle_set_backlight], bclp = 0x800000ff > [ 5.692865] [drm:intel_panel_get_max_backlight], max backlight PWM = 4648 > [ 5.692870] [drm:intel_panel_actually_set_backlight], set backlight PWM = 4648 > [ 5.693401] [drm:asle_set_backlight], bclp = 0x80000000 > [ 5.693408] [drm:intel_panel_get_max_backlight], max backlight PWM = 4648 > [ 5.693413] [drm:intel_panel_actually_set_backlight], set backlight PWM = 0 > > (We've added another debug print to asle_set_backlight.) > > For some reason we get two asle requests in a row. In the good kernel > it's the same request twice, in the bad kernel the second requests is > for 0 backlight. The register dumps seem to confirm this. > > Please try a recent kernel, with and without the the bisected bad commit Hi, I did try the tip of Linus git tree. However I can't make the kernel boot regardless bad commit or not. The kernel just hang there after grub2 load the kernel and initram image. It looks like a different problem than the intel black screen because it don't even get to the point show any console print out. I will try the intel branch instead. Chris
