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| author | Hsin-Yi Wang <hsinyi@chromium.org> | 2022-02-17 16:22:25 +0800 |
|---|---|---|
| committer | Robert Foss <robert.foss@linaro.org> | 2022-03-02 14:06:21 +0100 |
| commit | c0bbed9051b6eb293be6128d060bb49e999ef7d4 (patch) | |
| tree | 8ac8863392717b39080a8572ea1b21a52dd8dbd3 /drivers/gpu | |
| parent | 7e302637ba6192a2b432b327ab59ada6cb7907d4 (diff) | |
| download | linux-c0bbed9051b6eb293be6128d060bb49e999ef7d4.tar.bz2 | |
drm/bridge: Clear the DP_AUX_I2C_MOT bit passed in aux read command.
If the previous transfer didn't end with a command without DP_AUX_I2C_MOT,
the next read trasnfer will miss the first byte. But if the command in
previous transfer is requested with length 0, it's a no-op to anx7625
since it can't process this command. anx7625 requires the last command
to be read command with length > 0.
It's observed that if we clear the DP_AUX_I2C_MOT in read transfer, we
can still get correct data. Clear the read commands with DP_AUX_I2C_MOT
bit to fix this issue.
Fixes: adca62ec370c ("drm/bridge: anx7625: Support reading edid through aux channel")
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Xin Ji <xji@analogixsemi.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220217082224.1823916-1-hsinyi@chromium.org
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/bridge/analogix/anx7625.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c index 9aab879a8851..31ecf5626f1d 100644 --- a/drivers/gpu/drm/bridge/analogix/anx7625.c +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c @@ -253,6 +253,8 @@ static int anx7625_aux_trans(struct anx7625_data *ctx, u8 op, u32 address, addrm = (address >> 8) & 0xFF; addrh = (address >> 16) & 0xFF; + if (!is_write) + op &= ~DP_AUX_I2C_MOT; cmd = DPCD_CMD(len, op); /* Set command and length */ |