On Wed, 10 Jan 2024 at 22:19, Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx> wrote:
>
> Since the value of DP_TEST_BIT_DEPTH_8 is already left shifted, in the
> BPC unknown case, the additional shift causes spill over to the other
> bits of the [DP_CONFIGURATION_CTRL] register.
> Fix this by changing the return value of dp_link_get_test_bits_depth()
> in the BPC unknown case to (DP_TEST_BIT_DEPTH_8 >> DP_TEST_BIT_DEPTH_SHIFT).
>
> Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
For the patch itself:
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Additional note. Since this made me look at how DP_TEST_BIT_DEPTH is
handled in the driver, I stumbled upon dp_link_bit_depth_to_bpc() vs
dp_link_bit_depth_to_bpp(). These two functions look pretty redundant.
Since the former one is used only for the debugfs, please consider
sending a patch that removes it for the sake of using the latter one
and /3 in dp_test_data_show().
--
With best wishes
Dmitry
