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| author | Matthias Kaehlcke <mka@chromium.org> | 2019-10-02 12:44:06 -0700 |
|---|---|---|
| committer | Neil Armstrong <narmstrong@baylibre.com> | 2019-10-07 14:27:48 +0200 |
| commit | bee447e224b2645911c5d06e35dc90d8433fcef6 (patch) | |
| tree | 892a6b7226dd636cf637507b637d2e50f8bc938e /drivers/gpu/drm/tilcdc/tilcdc_plane.c | |
| parent | 4340ec45e895c4bd25e9bcdb3b88cd192fd9512c (diff) | |
drm/bridge: dw-hdmi: Refuse DDC/CI transfers on the internal I2C controller
The DDC/CI protocol involves sending a multi-byte request to the
display via I2C, which is typically followed by a multi-byte
response. The internal I2C controller only allows single byte
reads/writes or reads of 8 sequential bytes, hence DDC/CI is not
supported when the internal I2C controller is used. The I2C
transfers complete without errors, however the data in the response
is garbage. Abort transfers to/from slave address 0x37 (DDC) with
-EOPNOTSUPP, to make it evident that the communication is failing.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191002124354.v2.1.I709dfec496f5f0b44a7b61dcd4937924da8d8382@changeid
Diffstat (limited to 'drivers/gpu/drm/tilcdc/tilcdc_plane.c')
0 files changed, 0 insertions, 0 deletions