Hi, On Thu, Jul 09, 2020 at 04:40:56PM +0200, Hans de Goede wrote: > Hi, > > On 7/9/20 4:14 PM, Sam Ravnborg wrote: > > Hi Hans. > > > > On Wed, Jul 08, 2020 at 11:14:16PM +0200, Hans de Goede wrote: > > > Hi All, > > > > > > Here is v4 of my patch series converting the i915 driver's code for > > > controlling the panel's backlight with an external PWM controller to > > > use the atomic PWM API. See below for the changelog. > > > > Why is it that i915 cannot use the pwm_bl driver for backlight? > > I have not studied the code - just wondering. > > The intel_panel.c code deals with 7 different types of PWM controllers > which are built into the GPU + support for external PWM controllers > through the kernel's PWM subsystem. > > pwm_bl will work for the external PWM controller case, but not for > the others. On top of that the intel_panel code integrates which > the video BIOS, getting things like frequency, minimum value > and if the range is inverted (0% duty == backlight brightness max). > I'm not even sure if pwm_bl supports all of this, but even if it > does the intel_panel code handles this in a unified manner for > all supported PWM controllers, including the ones which are > an integral part of the GPU. Thanks for the explanation. This is a more complicated world than the usual embedded case with a single pwm, no BIOS etc. So it makes sense. Sam > > Regards, > > Hans > > > > > > Initially the plan was for this series to consist of 2 parts: > > > 1. convert the pwm-crc driver to support the atomic PWM API and > > > 2. convert the i915 driver's PWM code to use the atomic PWM API. > > > > > > But during testing I've found a number of bugs in the pwm-lpss and I > > > found that the acpi_lpss code needs some special handling because of > > > some ugliness found in most Cherry Trail DSDTs. > > > > > > So now this series has grown somewhat large and consists of 4 parts: > > > > > > 1. acpi_lpss fixes workarounds for Cherry Trail DSTD nastiness > > > 2. various fixes to the pwm-lpss driver > > > 3. convert the pwm-crc driver to support the atomic PWM API and > > > 4. convert the i915 driver's PWM code to use the atomic PWM API > > > > > > The involved acpi_lpss and pwm drivers do not see a whole lot of churn, > > > so the plan is to merge this all through drm-intel-next-queued (dinq) > > > once all the patches are reviewed / have acks. > > > > > > In v4 the ACPI patches have been Acked by Rafael and the i915 patches > > > have been acked by Jani. So that just leaves the PWM patches. > > > > > > Uwe can I get your ok / ack for merging this through the dinq branch > > > once you have acked al the PWM patches ? > > > > > > This series has been tested (and re-tested after adding various bug-fixes) > > > extensively. It has been tested on the following devices: > > > > > > -Asus T100TA BYT + CRC-PMIC PWM > > > -Toshiba WT8-A BYT + CRC-PMIC PWM > > > -Thundersoft TS178 BYT + CRC-PMIC PWM, inverse PWM > > > -Asus T100HA CHT + CRC-PMIC PWM > > > -Terra Pad 1061 BYT + LPSS PWM > > > -Trekstor Twin 10.1 BYT + LPSS PWM > > > -Asus T101HA CHT + CRC-PMIC PWM > > > -GPD Pocket CHT + CRC-PMIC PWM > > > > > > Changelog: > > > > > > Changes in v2: > > > - Fix coverletter subject > > > - Drop accidentally included debugging patch > > > - "[PATCH v3 02/15] ACPI / LPSS: Save Cherry Trail PWM ctx registers only once ( > > > - Move #define LPSS_SAVE_CTX_ONCE define to group it with LPSS_SAVE_CTX > > > > > > Changes in v3: > > > - "[PATCH v3 04/15] pwm: lpss: Add range limit check for the base_unit register value" > > > - Use base_unit_range - 1 as maximum value for the clamp() > > > - "[PATCH v3 05/15] pwm: lpss: Use pwm_lpss_apply() when restoring state on resume" > > > - This replaces the "pwm: lpss: Set SW_UPDATE bit when enabling the PWM" > > > patch from previous versions of this patch-set, which really was a hack > > > working around the resume issue which this patch fixes properly. > > > - PATCH v3 6 - 11 pwm-crc changes: > > > - Various small changes resulting from the reviews by Andy and Uwe, > > > including some refactoring of the patches to reduce the amount of churn > > > in the patch-set > > > > > > Changes in v4: > > > - "[PATCH v4 06/16] pwm: lpss: Correct get_state result for base_unit == 0" > > > - This is a new patch in v4 of this patchset > > > - "[PATCH v4 12/16] pwm: crc: Implement get_state() method" > > > - Use DIV_ROUND_UP when calculating the period and duty_cycle values > > > - "[PATCH v4 16/16] drm/i915: panel: Use atomic PWM API for devs with an external PWM controller" > > > - Add a note to the commit message about the changes in pwm_disable_backlight() > > > - Use the pwm_set/get_relative_duty_cycle() helpers > > > > > > Regards, > > > > > > Hans > > > > > > _______________________________________________ > > > dri-devel mailing list > > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > >
