https://bugs.freedesktop.org/show_bug.cgi?id=73530 --- Comment #41 from Paul Menzel --- Created attachment 92264 --> https://bugs.freedesktop.org/attachment.cgi?id=92264&action=edit Picture of another wrong timing(?) This morning I noticed the same behavior with the same patch. commit 7424173698775ad90a039d8e00cbee333de536ec Author: Alex Deucher Date: Tue Jan 14 10:45:51 2014 -0500 drm/radeon/dp: sleep after powering up the display According to the DP 1.1 spec, the sink must power up within 1ms. Noticed while reviewing Thierry's drm/dp patches. Signed-off-by: Alex Deucher diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index fb3ae07..ba7157a 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -671,9 +671,11 @@ static int radeon_dp_link_train_init(struct radeon_dp_link_train_info *dp_info) u8 tmp; /* power up the sink */ - if (dp_info->dpcd[0] >= 0x11) + if (dp_info->dpcd[0] >= 0x11) { radeon_write_dpcd_reg(dp_info->radeon_connector, DP_SET_POWER, DP_SET_POWER_D0); + usleep_range(1000, 2000); + } /* possibly enable downspread on the sink */ if (dp_info->dpcd[3] & 0x1) The attached picture was gotten after the first xrandr off/on cycle. The next xrandr off/on cycle got the display to work too. -- You are receiving this mail because: You are the assignee for the bug.