On 08/02/2013 02:44 PM, Felipe Contreras wrote: > On Thu, Aug 1, 2013 at 11:59 PM, Aaron Lu <aaron.lu@xxxxxxxxx> wrote: >> On 08/02/2013 12:50 PM, Felipe Contreras wrote: >>> On Thu, Aug 1, 2013 at 11:30 PM, Aaron Lu <aaron.lu@xxxxxxxxx> wrote: > >>>> Please see acpi_video_bqc_quirk, we set _BQC_use_index by revert the >>>> level on a reversed _BCL, so we will need to revert level here too. >>> >>> I cannot parse that sentence, but nothing needs to change there; to >>> find out if _BQC is using an index, we need to see if the returned >>> value is the index of the level we are looking for, and to find that >>> out we need the original list of levels, which can be found by >>> reverting the already reverted list. If this wasn't the case there >> >> Yes, but instead of reverting the already reverted list, we revert the >> returned value to get the correct index in the reverted list. But your >> patch removes the revert, is it correct? > > It removes the revert in acpi_video_bqc_value_to_level(), not > acpi_video_bqc_quirk(). If I remove both reverts it doesn't work on Of course I mean you remove the revert in acpi_video_bqc_value_to_level as is shown in your patch. > this machine, however, I think it works by accident. > > The initial _BCM commands don't work, so the level remains at 100%. > Since the level is max_level, acpi_video_bqc_quirk() tries with the > first level, which is 0, and 0 happens to be the index of 100. > > So _BQC is returning 100, which is not the index of 0 (what we tested > for), but actually 100. > > I think the current code is correct, but acpi_video_bqc_quirk() should > be testing br->levels[3], or anything other than 0/100 which can be > easily confused. > > If so, the code would find that _BQC doesn't work on this machine (in > win8 mode)... at least initially. My guess is that it only starts to > work after acpi_video_bus_start_devices() is called. > > Forcing br->flags._BQC_use_index = 0 seems to work. Seems ASUS machines tend to have this issue: https://bugzilla.kernel.org/show_bug.cgi?id=52951 https://bugzilla.kernel.org/show_bug.cgi?id=56711 I have a patch to enhance the quirk some time ago: https://github.com/aaronlu/linux/commit/0a3d2c5b59caf80ae5bb1ca1fda0f7bf448b38c9 But at that time we have decided to remove acpi video interface if this is a win8 system(all of these affected systems are win8), so I didn't submit it. Can you please give it a test? Perhaps I can send it now. -Aaron -- 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
