[PATCH v3 0/6] drm/vc4: hdmi: Fix CEC access while disabled

From: Maxime Ripard
Date: Thu Aug 19 2021 - 09:59:41 EST


Hi,

This series aims at fixing a complete and silent hang when one tries to use CEC
while the display output is off.

This can be tested with:

echo off > /sys/class/drm/card0-HDMI-A-1/status
cec-ctl --tuner -p 1.0.0.0
cec-compliance

This series addresses it by making sure the HDMI controller is powered up as
soon as the CEC device is opened by the userspace.

Let me know what you think,
Maxime

Changes from v2:
- Rebased on top of drm-misc-fixes
- Fixed a build error

Changes from v1:
- More fixes
- Added a big warning if we try to access a register while the device is
disabled.
- Fixed the pre_crtc_configure error path

Maxime Ripard (6):
drm/vc4: select PM
drm/vc4: hdmi: Make sure the controller is powered up during bind
drm/vc4: hdmi: Rework the pre_crtc_configure error handling
drm/vc4: hdmi: Split the CEC disable / enable functions in two
drm/vc4: hdmi: Make sure the device is powered with CEC
drm/vc4: hdmi: Warn if we access the controller while disabled

drivers/gpu/drm/vc4/Kconfig | 1 +
drivers/gpu/drm/vc4/vc4_hdmi.c | 125 ++++++++++++++++++----------
drivers/gpu/drm/vc4/vc4_hdmi_regs.h | 6 ++
3 files changed, 90 insertions(+), 42 deletions(-)

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2.31.1