Bug 41366 - [r600 KMS] HDMI on a Fusion board only comes up when LVDS is already enabled
Summary: [r600 KMS] HDMI on a Fusion board only comes up when LVDS is already enabled
Status: RESOLVED MOVED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Radeon (show other bugs)
Version: XOrg git
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: Default DRI bug account
QA Contact:
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Reported: 2011-09-30 10:12 UTC by Simon Farnsworth
Modified: 2019-11-19 08:20 UTC (History)
0 users

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i915 platform:
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Attachments
dmesg showing the modeset that results in HDMI being off unexpectedly (16.63 KB, text/plain)
2011-09-30 10:13 UTC, Simon Farnsworth 		no flags Details
dmesg showing the modeset that results in HDMI working (18.13 KB, text/plain)
2011-09-30 10:13 UTC, Simon Farnsworth 		no flags Details
use hardcoded dig encoder to transmitter mapping (1.30 KB, patch)
2011-10-05 15:35 UTC, Alex Deucher 		no flags Details | Splinter Review
View All

Description Simon Farnsworth 2011-09-30 10:12:18 UTC 
I'm running airlied's drm-fixes, git revision fdfc61594e6de21c23f955818ef78bcab9bafe40, and experiencing "interesting" times trying to get HDMI to work on a Fusion GPU (detected by X as [    49.876] (--) RADEON(0): Chipset: "AMD Radeon HD 6310 Graphics" (ChipID = 0x9802)).

If I run:
xrandr --output HDMI-0 --off
xrandr --output LVDS --auto
xrandr --output HDMI-0 --mode 1920x1200

the HDMI monitor comes up at 1920x1200

If I run:
xrandr --output HDMI-0 --off
xrandr --output LVDS --off
xrandr --output HDMI-0 --mode 1920x1200

the HDMI monitor immediately enters DPMS Off state, and stays there.

I've confirmed with "grep . /sys/class/drm/card0-HDMI-A-1/*" that the kernel thinks the HDMI connector is switched on. The only difference I can see is that HDMI works when it gets CRTC 1, but not when it gets CRTC 0.

I have captured logs from the kernel with drm.debug=0x6 during the runs, in case that explains what's going on; I will attach them to this bug.
Comment 1 Simon Farnsworth 2011-09-30 10:13:00 UTC 
Created attachment 51804 [details]
dmesg showing the modeset that results in HDMI being off unexpectedly
Comment 2 Simon Farnsworth 2011-09-30 10:13:24 UTC 
Created attachment 51805 [details]
dmesg showing the modeset that results in HDMI working
Comment 3 Alex Deucher 2011-10-05 15:08:22 UTC 
Strange, everything looks correct.  I'll dig into it.  Manually specifying the crtc seems to work, e.g.,

xrandr --output HDMI-0 --mode 1920x1200 --crtc 1
xrandr --output HDMI-0 --mode 1920x1200 --crtc 0
Comment 4 Alex Deucher 2011-10-05 15:35:55 UTC 
Created attachment 52024 [details] [review]
use hardcoded dig encoder to transmitter mapping

This patch fixes the issue for me.
Comment 5 Simon Farnsworth 2011-10-06 03:10:23 UTC 
Tested the patch - it works for me.
Comment 6 Florian Mickler 2012-01-12 14:46:12 UTC 
A patch referencing this bug report has been merged in Linux v3.1-rc10:

commit cb7cf41961fe10773c491c75ae73539ad4bbed66
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Wed Oct 5 18:36:50 2011 -0400

    drm/radeon/kms: use hardcoded dig encoder to transmitter mapping for DCE4.1
Comment 7 Martin Peres 2019-11-19 08:20:48 UTC 
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/drm/amd/issues/213.

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