On Mon, May 14, 2018 at 1:50 PM, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > On Thu, May 10, 2018 at 05:25:10PM +0200, Rafael J. Wysocki wrote: >> On Thursday, April 26, 2018 2:10:23 PM CEST Hans de Goede wrote: >> > On some devices the contents of the ctrl register get lost over a >> > suspend/resume and the PWM comes back up disabled after the resume. >> > >> > This is seen on some Bay Trail devices with the PWM in ACPI enumerated >> > mode, so it shows up as a platform device instead of a PCI device. >> > >> > If we still think it is enabled and then try to change the duty-cycle >> > after this, we end up with a "PWM_SW_UPDATE was not cleared" error and >> > the PWM is stuck in that state from then on. >> > >> > This commit adds suspend and resume pm callbacks to the pwm-lpss-platform >> > code, which save/restore the ctrl register over a suspend/resume, fixing >> > this. >> > >> > Note that: >> > >> > 1) There is no need to do this over a runtime suspend, since we >> > only runtime suspend when disabled and then we properly set the enable >> > bit and reprogram the timings when we re-enable the PWM. >> > >> > 2) This may be happening on more systems then we realize, but has been >> > covered up sofar by a bug in the acpi-lpss.c code which was save/restoring >> > the regular device registers instead of the lpss private registers due to >> > lpss_device_desc.prv_offset not being set. This is fixed by a later patch >> > in this series. >> > >> > Cc: stable@xxxxxxxxxxxxxxx >> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >> >> Andy, Thierry, any comments or concerns regarding this series? > > Hans said in the cover letter of the first version of this series that > he preferred to merge both patches through the PWM tree because of the > dependency. So I'm waiting for an Acked-by from you on the ACPI bits. OK, please feel free to add it to the patches, then. Thanks, Rafael -- 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
