On Fri, Nov 06, 2020 at 06:17:10PM -0500, Matt Turner wrote: > On my late 2013 Macbook Pro, I have a couple of scripts that set the > fans to auto or full-speed: > > fan-hi: > #!/bin/sh > sudo sh -c 'echo 1 > /sys/devices/platform/applesmc.768/fan1_manual > echo 1 > /sys/devices/platform/applesmc.768/fan2_manual > cat /sys/devices/platform/applesmc.768/fan1_max > /sys/devices/platform/applesmc.768/fan1_output > cat /sys/devices/platform/applesmc.768/fan2_max > /sys/devices/platform/applesmc.768/fan2_output' > > fan-auto: > #!/bin/sh > sudo sh -c 'echo 0 > /sys/devices/platform/applesmc.768/fan1_manual > echo 0 > /sys/devices/platform/applesmc.768/fan2_manual' > > Running ./fan-hi and then ./fan-auto on Linux v5.6 works and doesn't > cause any problems, but after updating to v5.9 I see this in dmesg: > > [Nov 6 17:24] applesmc: send_byte(0x01, 0x0300) fail: 0x40 > [ +0.000005] applesmc: FS! : write data fail > [ +0.191777] applesmc: send_byte(0x30, 0x0300) fail: 0x40 > [ +0.000009] applesmc: F0Tg: write data fail > [ +7.097416] applesmc: send_byte(0x00, 0x0300) fail: 0x40 > [ +0.000006] applesmc: FS! : write data fail > > and the fan controls don't work. > > Googling turned up this [1] which looks like the same problem. They said > it began occurring between v5.7 and v5.8, so I looked and found this > commit. > > After reverting commit fff2d0f701e6753591609739f8ab9be1c8e80ebb from > v5.9, I no longer see the errors in dmesg and the fan controls work > again. > > Any ideas what the problem is? > > Thanks, > Matt > > [1] https://stackoverflow.com/questions/63505469/cant-write-data-to-applesmc-error-after-upgrade-to-arch-linux-kernel-5-8-1 > There is another thread on this regression: https://lore.kernel.org/lkml/20200930105442.3f642f6c@aktux/ Looks like Brad Campbell has a patch that has some success in fixing the regression (although others are saying it breaks their setup...): https://lore.kernel.org/lkml/3c72ccc3-4de1-b5d0-423d-7b8c80991254@xxxxxxxxxxxxxxx/ Might be worth giving it a shot and jumping in so you get CC'd on further revisions. Cheers, Nathan
