On Mon, Sep 07, 2026 at 03:14:33PM +0530, Saurabh Anand wrote: > > On 24-08-2026 18:45, Konrad Dybcio wrote: > > On 8/24/26 1:28 PM, Saurabh Anand wrote: > > > drm_dp_lttpr_count() returns 0 when no LTTPRs are detected and a > > > negative value on error. The previous code passed the result directly > > > to drm_dp_lttpr_init() without checking, which would call into the > > > LTTPR transparency-mode setup with a zero or negative repeater count. > > > > > > Add an early return for lttpr_count <= 0 to skip the init entirely > > > when there are no repeaters in the link, matching the expected usage > > > of drm_dp_lttpr_init(). > > Reading the body of that function, I'm not sure your statement is true > > drm_dp_lttpr_count() returns 0 when no LTTPRs are detected and a > negative error code when the LTTPR common capabilities report an invalid > or unsupported repeater count. > > drm_dp_lttpr_init() already handles the zero-count case by returning > early. However, when passed a negative count, it still writes transparent > mode before returning -ENODEV.
And this is correct. If there are more than 8 LTTPRs, they must be switched to the transparent mode as it's impossible to control them individually. > > I will update the commit message giving more details. > > > > > Konrad -- With best wishes Dmitry
