From 4df54c493e76f3cfa0bc8c54c5c43faa3b6e78d4 Mon Sep 17 00:00:00 2001 From: Ilya Bakoulin Date: Tue, 26 Jul 2022 16:19:38 -0400 Subject: [PATCH] drm/amd/display: Fix pixel clock programming [ Upstream commit 04fb918bf421b299feaee1006e82921d7d381f18 ] [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 Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 2 ++ 1 file changed, 2 insertions(+) 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 054823d..5f1b735 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 @@ -545,9 +545,11 @@ 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; -- 2.7.4