Bug 94342

Summary:

Nvidia G96GLM 3840x2160@30 not functional with nouveau

Product:

xorg

Reporter:

Elmar Stellnberger <estellnb>

Component:

Driver/nouveau

Assignee:

Nouveau Project <nouveau>

Status:

RESOLVED WORKSFORME

QA Contact:

Xorg Project Team <xorg-team>

Severity:

normal

Priority:

medium

Version:

unspecified

Hardware:

x86-64 (AMD64)

OS:

Linux (All)

Whiteboard:

i915 platform:

i915 features:

Attachments:

Description	Flags
Xorg.0.log	none
journal	none
3840x2160@30 - snapshot of the monitor	none
mmiotrace of setting 3840x2160@30 with the proprietary driver	none
another mmiotrace of setting 3840x2160@30 with the proprietary driver	none

Description Elmar Stellnberger 2016-02-29 22:51:51 UTC

While my Nvidia G96GLM [Quadro FX 770M] yields 3840x2160@30 well under Windows 7 certain problems appear when trying to make use of that mode under nouveau/Linux. The 3840x2160_23.00 mode described in Bug 93405 works well also with the G96GLM; here even without any nouveau.hdmimhz parameter.
  A 3840x2160@30 mode appears automatically as soon as I specify nouveau.hdmimhz=297. However when I select it the external monitor turns white with a black bar at the bottom instead of showing the correct screen content. Trying predefined modelines by cvt, gtf or the arachnoid modeline calculator (online) does not yield any usable result either (blackscreens).
  Unfortunately many 4K screens only support at minimum 30Hz and not 23Hz so that this issue is a real problem. Besides this heavy mode switching can still lead to crashes/hangs while the 3840x2160@30-interlaced mode worked well even without a hdmimhz parameter. However for interlaced modes the mouse pointer still disappears.

Comment 1 Elmar Stellnberger 2016-02-29 22:53:22 UTC

Created attachment 122044 [details]
Xorg.0.log

Linux AmiloXi3650 4.5.0-rc4-ARCH #4 SMP PREEMPT Sat Feb 20 22:27:16 CET 2016 x86_64 GNU/Linux
X.Org X Server 1.18.1
Release Date: 2016-02-08

Comment 2 Elmar Stellnberger 2016-02-29 22:53:53 UTC

Created attachment 122045 [details]
journal

Comment 3 Elmar Stellnberger 2016-02-29 22:54:31 UTC

Created attachment 122046 [details]
3840x2160@30 - snapshot of the monitor

Comment 4 Elmar Stellnberger 2016-04-17 10:16:33 UTC

4.6.0-rc2-ARCH-00004-g603539d: As soon as I boot with a hdmimhz=297 I get a blackscreen though the graphics card is known to work with 3840x2160@30 under Windows; i.e. that should work.

Comment 5 Elmar Stellnberger 2016-04-28 12:36:32 UTC

same problem with 4.6.0-rc5-ARCH-00005-g0b20a43.

Comment 6 Elmar Stellnberger 2016-05-04 07:10:59 UTC

Created attachment 123450 [details]
mmiotrace of setting 3840x2160@30 with the proprietary driver

Comment 7 Elmar Stellnberger 2016-05-04 07:13:59 UTC

Created attachment 123451 [details]
another mmiotrace of setting 3840x2160@30 with the proprietary driver

Comment 8 Elmar Stellnberger 2016-05-18 09:08:58 UTC

same with 4.6.0-ARCH-00466-ge80ac9b.

Comment 9 Elmar Stellnberger 2016-05-18 12:35:41 UTC

  As it turned out a refresh rate of 30Hz can be achieved with the OSS-driver and the right modeline:

  Modeline "3840x2160_30.00"  268.06  3840 3992 4080 4112  2160 2161 2164 2173 +hsync -vsync

  It is a trick to set nouveau.hdmimhz=296 instead of 297 in order to prevent the automatic mode requiring a higher TMDS frequency to appear automatically which blackens the screen. Once a mode with too high frequency has been set the external monitor will stay without signal until I reboot. In a practice the TMDS limit may neither be 225 nor 297 but somewhere in between.

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