On Thu, Mar 09, 2023 at 04:30:27PM -0500, Hamza Mahfooz wrote: > We should be checking if drm_dp_dpcd_read() returns the size that we are > asking it to read instead of just checking if it is greater than zero. > Also, we should WARN_ON() here since this condition is only ever met, if > there is an issue worth investigating. So, compare the return value of > drm_dp_dpcd_read() to size and WARN_ON() if they aren't equal. > > Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx> > --- > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c > index 8d598b322e5b..ed2ed7b1d869 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c > @@ -511,8 +511,8 @@ bool dm_helpers_dp_read_dpcd( > return false; > } > > - return drm_dp_dpcd_read(&aconnector->dm_dp_aux.aux, address, > - data, size) > 0; > + return !WARN_ON(drm_dp_dpcd_read(&aconnector->dm_dp_aux.aux, address, > + data, size) != size); Just FYI there are devices out there that violate the DP spec and reads from specific DPCD registers simply fail instead of returning the expected 0. > } > > bool dm_helpers_dp_write_dpcd( > -- > 2.39.2 -- Ville Syrjälä Intel
