Hi, On 11/21/23 11:33, Takashi Iwai wrote: > On Tue, 21 Nov 2023 11:21:53 +0100, > Hans de Goede wrote: >> >> Hi, >> >> On 11/21/23 10:52, Takashi Iwai wrote: >>> On Tue, 21 Nov 2023 10:19:03 +0100, >>> Thorsten Leemhuis wrote: >>>> >>>> Takashi, Jean-Jacques Hiblot, Lee, >>>> >>>> On 20.11.23 14:53, Takashi Iwai wrote: >>>>> On Mon, 06 Nov 2023 14:19:08 +0100, >>>>> Bagas Sanjaya wrote: >>>>>> On Sat, Nov 04, 2023 at 01:01:56PM +0100, Jean-Jacques Hiblot wrote: >>>>>>> On 29/10/2023 02:48, Bagas Sanjaya wrote: >>>>>>>> On Thu, Oct 26, 2023 at 02:55:06PM +0700, Bagas Sanjaya wrote: >>>>>>>>> The culprit seems to be commit c7d80059b086c4986cd994a1973ec7a5d75f8eea, which introduces a new 'color' attribute for led sysfs class devices. The problem is that the system76-acpi platform driver tries to create the exact same sysfs attribute itself for the system76_acpi::kbd_backlight device, leading to the conflict. For testing purposes, I've just rebuilt the kernel with the system76-apci color attribute renamed to kb_color, and that fixes the issue. >>>>>>>> >>>>>>>> Jean-Jacques Hiblot, would you like to take a look on this regression, >>>>>>>> since you authored the culprit? >>>>> >>>>>>> The offending commit stores the color in struct led_classdev and exposes it >>>>>>> via sysfs. It was part of a series that create a RGB leds from multiple >>>>>>> single-color LEDs. for this series, we need the color information but we >>>>>>> don't really need to expose it it via sysfs. In order to fix the issue, we >>>>>>> can remove the 'color' attribute from the sysfs. >>>>>> >>>>>> OK, see you in the patch! >>>>> >>>>> Is there a patch available? >>>> >>>> Not that I know of. Could not find anything on lore either. >>>> >>>>> This bug hits for a few Logitech keyboard models, too, and it makes >>>>> 6.6 kernel unsable for them, as hid-lg-g15 driver probe fails due to >>>>> this bug: >>>>> https://bugzilla.kernel.org/show_bug.cgi?id=218155 >>>>> >>>>> We need a quick fix for 6.6.x. >>>> >>>> Given that Jean-Jacques Hiblot (the author of the culprit) and Lee (who >>>> committed it and sent it to Linus) know about this for a while already >>>> without doing anything about it, I wonder if someone should just send a >>>> revert to Linus (unless of course that is likely to introduce a >>>> regression on its own). >>>> >>>> Takashi, could you maybe do this, unless a fix shows up real soon? >>> >>> I can, but we need to decide which way to go. >>> There are several options: >>> >>> 1. Revert the commit c7d80059b086; >>> this drops led class color sysfs entries. Also the store of >>> led_cdev->color from fwnode is dropped, too. >>> >>> 2. Drop only led class color sysfs entries; >>> a partial revert of c7d80059b086 above >> >> AFAIK further up in the thread (or a related thread) there >> already was consensus to do this. Someone just needs to >> write the patch. > > Well, is there any user of this new led_classdev.color field? > The value read from fwnode is stored there, but as far as I see, there > seems no real user, so far. If it's still unused, we can do the whole > revert -- which is cleaner. I honestly don't know. I've mostly just been reading along. I think there may be some future in kernel use planned (not sure at all though). If there are no current in kernel users then I agree we should just go with a full revert now to fix the regression. If some later in kernel users do come along then they can always re-introduce the change minus the sysfs attr addition. Regards, Hans
