Hi, On 10/7/21 11:54 AM, Hans de Goede wrote: > Hi, > > On 10/5/21 10:26 PM, Lyude Paul wrote: >> On Sat, 2021-10-02 at 11:14 +0200, Hans de Goede wrote: >>> Hi Lyude, >>> >>> On 10/2/21 12:53 AM, Lyude Paul wrote: >>>> When I originally moved all of the VESA backlight code in i915 into DRM >>>> helpers, one of the things I didn't have the hardware or time for >>>> testing was machines that used a combination of PWM and DPCD in order to >>>> control their backlights. This has since then caused some breakages and >>>> resulted in us disabling DPCD backlight support on such machines. This >>>> works fine, unless you have a machine that actually needs this >>>> functionality for backlight controls to work at all. Additionally, we >>>> will need to support PWM for when we start adding support for VESA's >>>> product (as in the product of multiplication) control mode for better >>>> brightness ranges. >>>> >>>> So - let's finally finish up implementing basic support for these types >>>> of backlights to solve these problems in our DP helpers, along with >>>> implementing support for this in i915. And since digging into this issue >>>> solved the last questions we really had about probing backlights in i915 >>>> for the most part, let's update some of the comments around that as >>>> well! >>> >>> Backlight control is a topic which I'm reasonably familiar with, >>> do you want me to review this series for you ? >> >> Possibly, although I definitely want to make sure that someone from Intel gets >> a chance to review this as well. > > I already expected you would also want someone from Intel to take a look > as well :) > > So to figure out if I have system to test this I ended up taking a close > look at the code, which was a nice learning experience. Interesting how > some panels use a combination of DCPD + pwm/gpio for enable/disable and/or > pwm for brightness level control. > > I wonder though what DCPD still does if pwm is used for both the > enable/disable and brightness-level control ? > > Since I was taking a close look already I decided to do turn this into > a full, the entire set looks good to me: > > Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> > >> I'm more curious if you might happen to have >> any systems that would be able to test this. > > I don't believe I have a system where I can test this, The only systems > which I have which presumably (I did not check) use eDP / DCPD backlight > control are boring ThinkPads with only i915 gfx. Continuing with reading my email I see that you've also posted a v5 with 1 new patch: [PATCH v3 3/5] drm/dp: Disable unsupported features in DP_EDP_BACKLIGHT_MODE_SET_REGISTER That patch looks good to me too, so you may also add my: Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> To that one / to the entire v3 series. Regards, Hans >>>> Changes: >>>> * Fixup docs >>>> * Add patch to stop us from breaking nouveau >>>> >>>> Lyude Paul (4): >>>> drm/i915: Add support for panels with VESA backlights with PWM >>>> enable/disable >>>> drm/nouveau/kms/nv50-: Explicitly check DPCD backlights for aux >>>> enable/brightness >>>> drm/dp, drm/i915: Add support for VESA backlights using PWM for >>>> brightness control >>>> drm/i915: Clarify probing order in intel_dp_aux_init_backlight_funcs() >>>> >>>> drivers/gpu/drm/drm_dp_helper.c | 75 +++++++++++------ >>>> .../drm/i915/display/intel_dp_aux_backlight.c | 80 ++++++++++++++----- >>>> drivers/gpu/drm/nouveau/nouveau_backlight.c | 5 +- >>>> include/drm/drm_dp_helper.h | 7 +- >>>> 4 files changed, 122 insertions(+), 45 deletions(-) >>>> >>> >>
