From: Ilya Bakoulin Date: Tue, 26 Jul 2022 20:19:38 +0000 (-0400) Subject: drm/amd/display: Fix pixel clock programming X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=04fb918bf421b299feaee1006e82921d7d381f18;p=linux.git drm/amd/display: Fix pixel clock programming [Why] Some pixel clock values could cause HDMI TMDS SSCPs to be misaligned between different HDMI lanes when using YCbCr420 10-bit pixel format. BIOS functions for transmitter/encoder control take pixel clock in kHz increments, whereas the function for setting the pixel clock is in 100Hz increments. Setting pixel clock to a value that is not on a kHz boundary will cause the issue. [How] Round pixel clock down to nearest kHz in 10/12-bpc cases. Reviewed-by: Aric Cyr Acked-by: Brian Chang Signed-off-by: Ilya Bakoulin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c index 213de8cabfadb..165392380842a 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c @@ -543,9 +543,11 @@ static void dce112_get_pix_clk_dividers_helper ( switch (pix_clk_params->color_depth) { case COLOR_DEPTH_101010: actual_pixel_clock_100hz = (actual_pixel_clock_100hz * 5) >> 2; + actual_pixel_clock_100hz -= actual_pixel_clock_100hz % 10; break; case COLOR_DEPTH_121212: actual_pixel_clock_100hz = (actual_pixel_clock_100hz * 6) >> 2; + actual_pixel_clock_100hz -= actual_pixel_clock_100hz % 10; break; case COLOR_DEPTH_161616: actual_pixel_clock_100hz = actual_pixel_clock_100hz * 2;