Bug 89805 - [GM45 DP-DVI dongle] KMS often does not set native display resolution
Summary: [GM45 DP-DVI dongle] KMS often does not set native display resolution
Status: CLOSED INVALID
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: DRI git
Hardware: Other All
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-03-28 20:43 UTC by andreas.sturmlechner
Modified: 2017-07-24 22:47 UTC (History)
1 user (show)

See Also:
i915 platform: GM45
i915 features: display/DP


Attachments
20150328-2050_4.0.0-rc5+-start_dmesg-ignorelid_wrong-res.log (94.56 KB, text/plain)
2015-03-28 20:43 UTC, andreas.sturmlechner
no flags Details
20150328-2050_4.0.0-rc5+-start_dmesg-ignorelid_right-res.log (96.70 KB, text/plain)
2015-03-28 20:44 UTC, andreas.sturmlechner
no flags Details
20150328-2050_4.0.0-rc5+-start_dmesg-wrong-res.log (102.74 KB, text/plain)
2015-03-28 20:45 UTC, andreas.sturmlechner
no flags Details
20150328-2050_4.0.0-rc5+-start_dmesg-right-res.log (106.87 KB, text/plain)
2015-03-28 20:46 UTC, andreas.sturmlechner
no flags Details

Description andreas.sturmlechner 2015-03-28 20:43:14 UTC
Created attachment 114684 [details]
20150328-2050_4.0.0-rc5+-start_dmesg-ignorelid_wrong-res.log

This is a followup to bug 58876. My setup is a Thinkpad X200s (lid closed) sitting on an Ultrabase docking station, connected to a 1920x1200 DVI monitor by means of a DP-DVI dongle. 4.0.0 is the first kernel version since 3.7 that always seems to detect my external display: What previously most of the time ended with a black screen / standby now seems to have been replaced with KMS not setting the correct resolution. In the end KDE adjusts this correctly anyway, so this behaviour is already a big improvement, but it would be nice to get this ironed out as well.

I usually have to set i915.panel_ignore_lid=0 so that KMS is able to use all of the external screen estate and make it not align a limited output to the upper and left side, this setting also affects outcome with this bug:

If i915.panel_ignore_lid=0, then some very low standard resolution is set.
else, the LVDS panel's native resolution seems to be set for the external screen.
Comment 1 andreas.sturmlechner 2015-03-28 20:44:45 UTC
Created attachment 114685 [details]
20150328-2050_4.0.0-rc5+-start_dmesg-ignorelid_right-res.log
Comment 2 andreas.sturmlechner 2015-03-28 20:45:45 UTC
Created attachment 114686 [details]
20150328-2050_4.0.0-rc5+-start_dmesg-wrong-res.log

(really low resolution mode here)
Comment 3 andreas.sturmlechner 2015-03-28 20:46:17 UTC
Created attachment 114687 [details]
20150328-2050_4.0.0-rc5+-start_dmesg-right-res.log
Comment 4 Ville Syrjala 2015-03-30 06:19:18 UTC
Please grab the logs with drm.debug=0xe. drm.debug=1 doesn't really provide usefule debug information for modeset issues.
Comment 5 Chris Wilson 2015-03-30 08:24:03 UTC
This seems to be expected behaviour. The external outputs will not be available when KMS takes over, and so they will be hotplugged in later when the dock is enabled. As a result the initial resolution is computed solely for the eDP, which will then be mirrored onto the new outputs when they arrived. If they are all available, then the mode chosen will be one common for all outputs (probably still end up with some mismatch).
Comment 6 andreas.sturmlechner 2015-03-30 10:33:01 UTC
(In reply to Chris Wilson from comment #5)
> The external outputs will not be available when KMS takes over, and so they
> will be hotplugged in later when the dock is enabled. As a result the initial
> resolution is computed solely for the eDP, which will then be mirrored onto the
> new outputs when they arrived.

Except that 3.4.x on that particular setup and any other kernel on the same dock (but connected to a DP screen), together with i915.panel_ignore_lid=0 is always able to set the correct initial resolution - the dock is enabled from the start. It only happens in conjunction with the DP-DVI connector that it does not behave as expected (but much better than pre-4.0.0).

I can send new debug logs on the weekend.
Comment 7 Jani Nikula 2015-10-23 12:12:07 UTC
Timeout, closing. Please reopen if the problem persists with latest kernels.
Comment 8 andreas.sturmlechner 2015-10-25 21:58:48 UTC
(In reply to Jani Nikula from comment #7)
> Timeout, closing. Please reopen if the problem persists with latest kernels.

This is indeed always working now in 4.2. Sorry about forgetting to report.
Comment 9 Jani Nikula 2015-10-26 09:20:06 UTC
(In reply to andreas.sturmlechner from comment #8)
> (In reply to Jani Nikula from comment #7)
> > Timeout, closing. Please reopen if the problem persists with latest kernels.
> 
> This is indeed always working now in 4.2. Sorry about forgetting to report.

No worries, thanks for the follow-up!


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