_BQC seems to always return zero making backlight control to not work properly, i.e. only 2 lower brightness levels are available. Problem showed up after a bunch of fixes in acpi/video.c: 994fa63c5b126df6e9f31ef4e09000e2e243234b "ACPI / video: Fix applying indexed initial brightness value." 2d4128a25206685aaccaf14220c8436b11c6dc01 "ACPI / video: Make logic a little easier to understand." a89803df9c9b2d023227c48503066a728f1fed36 "ACPI / video: Fix brightness control initialization for some laptops." With this commits reverted controls works fine but only because BQC get's disabled due to invalid value being returned on initial BQC call.
Created attachment 96721 [details] dmidecode output
Created attachment 96731 [details] acpidump output
Created attachment 96741 [details] disassembled DSDT
Created attachment 96751 [details] Enhance _BQC quirk check Hi Artem, Please test if this patch fixed the problem, thanks. Apply on top of the -next tree.
Hi Aaron, Yes, this patch works for me. BQC is disabled on init as intended.
(In reply to comment #5) > Hi Aaron, > > Yes, this patch works for me. BQC is disabled on init as intended. And does it work as expected afterwards?
Yes it just uses backlight->curr so things are back to normal, i.e. both buttons and xbacklight work normally.
Hi Artem, I'll mark this bug as a duplicate of #42861, though they are not exactly the same, but they share something in common and can be solve in the same way. And I just proposed an updated patch, it shouldn't affect you, but if you have time, please kindly give it a test, thanks. *** This bug has been marked as a duplicate of bug 42861 ***