<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <style type="text/css" style="display:none;"></style> </head> <body dir="ltr"> <div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr"> I thought there was a patch to do this already that got sent out a few weeks ago. Basically limit ST/CZ to modes that do not require a retimer. Is an additional patch needed? Alex </div> <hr style="display:inline-block;width:98%" tabindex="-1"> <div id="divRplyFwdMsg" dir="ltr">From: amd-gfx <amd-gfx-bounces@lists.freedesktop.org> on behalf of S, Shirish <Shirish.S@amd.com> Sent: Monday, November 26, 2018 1:36:30 AM To: Li, Sun peng (Leo); Wentland, Harry Cc: amd-gfx@lists.freedesktop.org; S, Shirish Subject: [PATCH] drm/amd/display: limit high pixel clock modes on ST/CZ <div> </div> </div> <div class="BodyFragment"> <div class="PlainText">[Why] ST/CZ (dce110) advertises modes such as 4k@60Hz etc., that it cannot handle correctly, hence resulting in several issues like flickering, black lines/flashes and so on. [How] These modes are basically high pixel clock ones, hence limit the same to be advertised to avoid bad user experiences Signed-off-by: Shirish S <shirish.s@amd.com> Suggested-by: Harry Wentland <harry.wentland@amd.com> --- .../gpu/drm/amd/display/dc/dce110/dce110_timing_generator.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_timing_generator.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_timing_generator.c index 1b2fe0d..1b8fe99 100644 --- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_timing_generator.c +++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_timing_generator.c @@ -1121,6 +1121,16 @@ bool dce110_timing_generator_validate_timing( if (!timing) return false; + /* Limit all modes that have a high pixel clock + * which seems to be problematic on dce110 + * These include: 4k@60Hz, 1080p@144Hz,1440p@120Hz + * based on the below formula: + * refresh rate = pixel clock / (htotal * vtotal) + */ + if (timing->pix_clk_khz > 300000) + return false; + + hsync_offset = timing->h_border_right + timing->h_front_porch; h_sync_start = timing->h_addressable + hsync_offset; -- 2.7.4 _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org <a href="https://lists.freedesktop.org/mailman/listinfo/amd-gfx">https://lists.freedesktop.org/mailman/listinfo/amd-gfx</a> </div> </div> </body> </html>