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

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Message-Id: <20210819135931.895976-1-maxime@cerno.tech>
Date:   Thu, 19 Aug 2021 15:59:25 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     dri-devel@...ts.freedesktop.org,
        Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>
Cc:     linux-kernel@...r.kernel.org,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Tim Gover <tim.gover@...pberrypi.com>,
        Dom Cobley <dom@...pberrypi.com>,
        Boris Brezillon <bbrezillon@...nel.org>,
        linux-rpi-kernel@...ts.infradead.org,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        bcm-kernel-feedback-list@...adcom.com,
        Emma Anholt <emma@...olt.net>,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Maxime Ripard <mripard@...nel.org>
Subject: [PATCH v3 0/6] drm/vc4: hdmi: Fix CEC access while disabled

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(-)

-- 
2.31.1