On Fri, Aug 2, 2013 at 6:47 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Friday, August 02, 2013 02:37:09 PM Felipe Contreras wrote: >> If the _BCL package is descending, the first level (br->levels[2]) will >> be 0, and if the number of levels matches the number of steps, we might >> confuse a returned level to mean the index. >> >> For example: >> >> current_level = max_level = 100 >> test_level = 0 >> returned level = 100 >> >> In this case 100 means the level, not the index, and _BCM failed. But if >> the _BCL package is descending, the index of level 0 is also 100, so we >> assume _BQC is indexed, when it's not. >> >> This causes all _BQC calls to return bogus values causing weird behavior >> from the user's perspective. For example: xbacklight -set 10; xbacklight >> -set 20; would flash to 90% and then slowly down to the desired level >> (20). >> >> The solution is simple; test anything other than the first level (e.g. >> 1). >> >> Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> > > Looks reasonable. > > Aaron, what do you think? Aaron has a similar patch does many more checks. I think we should add more checks, but I think those should go into a separate patch. This patch alone fixes a real problem, which is rather urgent to fix, and I did it this way so it's trivial to review and merge. -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
