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 ? 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(-) >
