Hi, a new laptop model we've been struggling has some strange hardware configuration. BIOS turns off backlight and skips its initialization when the machine is booted with the lid closed. This leaves BLC_PWM_PCH_CTL2 and other registers uninitialized. Because a proper max brightness value can't be obtained from this register, i915 driver doesn't create the own backlight control any more. It results in the permanent blank screen even after the lid is opened. Actually, the only missing piece is the initial BLC_PWM_PCH_CTL2 value. If I overwrite it via intel_reg_write before loading i915 module, everything works fine. Now I wonder whether we can get this max brightness value from somewhere else. Is it defined in VBT or anywhere else persistent? thanks, Takashi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
