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[Bug,73530] Asus U38N: Black screen with Radeon driver in Linux 3.10, 3.11 and 3.12

Message ID bug-73530-502-3O1qqMrp6Q@http.bugs.freedesktop.org/ (mailing list archive)
State New, archived
Headers show

Commit Message

bugzilla-daemon@freedesktop.org Jan. 17, 2014, 8:38 a.m. UTC 
https://bugs.freedesktop.org/show_bug.cgi?id=73530

--- Comment #41 from Paul Menzel <paulepanter@users.sourceforge.net> ---
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 <alexander.deucher@amd.com>
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 <alexander.deucher@amd.com>

        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.
diff mbox

Patch

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 */