Hi,

On Mon, Aug 18, 2025 at 1:11 PM Doug Anderson [off-list ref] wrote:

Hi,

On Mon, Aug 18, 2025 at 4:50 AM Pin-yen Lin [off-list ref] wrote:

quoted

Some touch controllers have to be powered on after the panel's backlight
is enabled. To support these controllers, introduce .panel_enabled() and
.panel_disabling() to panel_follower_funcs and use them to power on the
device after the panel and its backlight are enabled.

Signed-off-by: Pin-yen Lin <redacted>

---

Changes in v3:
- Update kernel-docs of drm_panel_add_follower() and drm_panel_remove_follower()
- Fix the order of calling .panel_disabling() and .panel_unpreparing()
- Add a blank line before the goto label

Changes in v2:
- Replace after_panel_enabled flag with enabled/disabling callbacks

 drivers/gpu/drm/drm_panel.c | 73 +++++++++++++++++++++++++++++++------
 include/drm/drm_panel.h     | 14 +++++++
 2 files changed, 76 insertions(+), 11 deletions(-)

Looks good to me now.

Reviewed-by: Douglas Anderson <dianders@chromium.org>

If there are no objections, I'll plan to apply patch #1 next week to
give people a little time to speak up. As per discussion in v2 [1],
unless we hear back an "Ack" from HID maintainers then patch #2 will
just need to wait a while before it can land in the HID tree.

Question for Jessica / Neil: what do you think about landing
${SUBJECT} patch in drm-misc-fixes instead of drm-misc-next? This is a
dependency for the next patch which is marked as a "Fix". It'll mean
that the patch can make it into mainline faster so the HID patch could
land faster. The patch is also pretty low risk...

[1] https://lore.kernel.org/r/CAD=FV=UV8_XGmxC=7Z18PEnj6wKz+yZQuV_4h+LJh_MNCqszvg@mail.gmail.com/ (local)

I didn't hear anything and it didn't seem urgent enough to put in
Fixes. Pushed to drm-misc-next.

[1/2] drm/panel: Allow powering on panel follower after panel is enabled
      commit: 2eb22214c132374e11e681c44d7879c91f67f614