Bug 35903

Summary:

[915GM bisected] Two black flickers when probing inputs with drm-intel-fixes

Product:

DRI

Reporter:

Sitsofe Wheeler <sitsofe>

Component:

DRM/Intel

Assignee:

Chris Wilson <chris>

Status:

CLOSED FIXED

QA Contact:

Severity:

normal

Priority:

medium

CC:

jbarnes

Version:

XOrg git

Hardware:

x86 (IA32)

OS:

Linux (All)

Whiteboard:

i915 platform:

i915 features:

Attachments:

Description	Flags
git bisection log	none
intel_reg_dumper output for 9db reverted	none
intel_reg_dumper output for 9db	none
intel_reg_dumper output for intel-fixes + spurious inputs fix	none
drm/i915/tv: Fix modeset flickering introduced in 7f58aabc369014fda3a4a33604ba0a1b63b941ac	none

Description Sitsofe Wheeler 2011-04-02 03:22:03 UTC

Description of the problem:
When Plymouth/Xorg is starting or when xrandr is run the screen goes black then comes back then goes black then comes back in the space of about a second.


Steps to reproduce:
1. Start EeePC .
2. Let the boot finish and log in.
3. Start a terminal and run
xrandr

Expected result:
Extra text to appear in the terminal.

Actual result:
Before xrandr prints the text, the whole screen will go black then return then go black and then return again within the space of about a second creating a flickering effect.

How reproducible is the problem:
The problem is reproducible every time.

Version information:
EeePC 900
Ubuntu 10.04 (so an old xorg)
Kernel: 7f58aabc369014fda3a4a33604ba0a1b63b941ac (drm-intel-fixes)

Additional information:
This problem does not occur on 2.6.38 or below. A bisection narrowed it down to the following commit:

commit 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Feb 7 12:26:52 2011 -0800

    drm/i915: cleanup per-pipe reg usage
    
    We had some conversions over to the _PIPE macros, but didn't get
    everything.  So hide the per-pipe regs with an _ (still used in a few
    places for legacy) and add a few _PIPE based macros, then make sure
    everyone uses them.
    
    [update: remove usage of non-existent no-op macro]
    [update 2: keep modesetting suspend/resume code, update to new reg names]
    Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    [ickle: stylistic cleanups for checkpatch and taste]
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Reverting this makes the problem go away.

While a later patch ( 548f245ba6a318ef93f4d79bcc15cfe59a86f0d5 ) fixes the double height cursor that 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7 introduces, it does not fix the flickering.

Comment 1 Sitsofe Wheeler 2011-04-02 03:24:46 UTC

Created attachment 45155 [details]
git bisection log

Comment 2 Chris Wilson 2011-04-02 03:25:29 UTC

Let's compare the output of intel_reg_dumper with 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7^ and drm-intel-fixes.

Comment 3 Sitsofe Wheeler 2011-04-02 04:32:16 UTC

--- intel_reg_dumper.9db-reverted       2011-04-02 12:12:02.359380868 +0100
+++ intel_reg_dumper.7f5-dirty  2011-04-02 12:29:00.771442065 +0100
@@ -42,7 +42,7 @@
         PP_ON_DELAYS: 0x025807d0
        PP_OFF_DELAYS: 0x01f407d0
           PP_DIVISOR: 0x00251b05
-        PFIT_CONTROL: 0x00000000
+        PFIT_CONTROL: 0x00000008
      PFIT_PGM_RATIOS: 0x00000000
      PORT_HOTPLUG_EN: 0x00000000
    PORT_HOTPLUG_STAT: 0x00000000
@@ -55,7 +55,7 @@
          DSPATILEOFF: 0x00000000
            PIPEACONF: 0x80000000 (enabled, single-wide)
             PIPEASRC: 0x04ff03ff (1280, 1024)
-           PIPEASTAT: 0x84040203 (status: FIFO_UNDERRUN SVBLANK_INT_ENABLE VSYNC_INT_STATUS VBLANK_INT_STATUS OREG_UPDATE_STATUS)
+           PIPEASTAT: 0x80000203 (status: FIFO_UNDERRUN VSYNC_INT_STATUS VBLANK_INT_STATUS OREG_UPDATE_STATUS)
    PIPEA_GMCH_DATA_M: 0x00000000
    PIPEA_GMCH_DATA_N: 0x00000000
      PIPEA_DP_LINK_M: 0x00000000
@@ -79,7 +79,7 @@
           DSPBSTRIDE: 0x00000a00 (2560 bytes)
              DSPBPOS: 0x00000000 (0, 0)
             DSPBSIZE: 0x03ff04ff (1280, 1024)
-            DSPBBASE: 0x00000000
+            DSPBBASE: 0x0012c000
             DSPBSURF: 0x00000000
          DSPBTILEOFF: 0x00000000
            PIPEBCONF: 0x80000000 (enabled, single-wide)
@@ -195,6 +195,6 @@
             FENCE  5: 0x00000000 (disabled)
             FENCE  6: 0x00000000 (disabled)
             FENCE  7: 0x00000000 (disabled)
-             INST_PM: 0x00000000
+             INST_PM: 0x00000800
 pipe A dot 108000 n 2 m1 14 m2 8 p1 2 p2 10
 pipe B dot 50057 n 3 m1 11 m2 6 p1 2 p2 14

Comment 4 Sitsofe Wheeler 2011-04-02 04:53:52 UTC

Created attachment 45158 [details]
intel_reg_dumper output for 9db reverted

intel_reg_dumper output for a reverted 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7 (so effectively 8d7e3de1e019238211fa06e109437a13cae62004)

Comment 5 Sitsofe Wheeler 2011-04-02 04:55:05 UTC

Created attachment 45159 [details]
intel_reg_dumper output for 9db

intel_reg_dumper output for 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7 .

Comment 6 Sitsofe Wheeler 2011-04-02 04:58:41 UTC

Created attachment 45160 [details]
intel_reg_dumper output for intel-fixes + spurious inputs fix

intel_reg_dumper output for 7f58aabc369014fda3a4a33604ba0a1b63b941ac + a fix to detect attached outputs correctly (so that at least the screen resolution used between all the dumps is the same).

Comment 7 Sitsofe Wheeler 2011-04-09 10:32:22 UTC

Created attachment 45445 [details] [review]
drm/i915/tv: Fix modeset flickering introduced in 7f58aabc369014fda3a4a33604ba0a1b63b941ac

The tidy ups in 7f58aabc369014fda3a4a33604ba0a1b63b941ac ("drm/i915: cleanup per-pipe reg usage") changed intel_crtc->plane to intel_crtc->pipe in intel_tv_mode_set(). This caused the screen to quickly turn off before returning whenever modesetting/mode probing took place on my 915GM EeePC 900 creating a flickering effect. This patch changes intel_crtc->pipe back to intel_crtc->plane which solves the problem for me.

References: https://bugs.freedesktop.org/show_bug.cgi?id=35903
Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>

Comment 8 Chris Wilson 2011-04-09 12:01:06 UTC

Thanks Sitosfe!

Comment 9 Chris Wilson 2011-04-13 04:05:03 UTC

Sitsofe, thanks for the patch:

commit ccacfec6cc22157971bd970486fd3fd4972b8e2e
Author: Sitsofe Wheeler <sitsofe@yahoo.com>
Date:   Tue Apr 12 06:51:39 2011 +0100

    drm/i915/tv: Fix modeset flickering introduced in 7f58aabc3
    
    The tidy ups in 7f58aabc369014fda3a4a33604ba0a1b63b941ac ("drm/i915:
    cleanup per-pipe reg usage") changed intel_crtc->plane to intel_crtc->pipe i
    intel_tv_mode_set(). This caused the screen to quickly turn off before
    returning whenever modesetting/mode probing took place on my 915GM EeePC
    900 creating a flickering effect. This patch changes intel_crtc->pipe back
    to intel_crtc->plane which solves the problem for me.
    
    References: https://bugs.freedesktop.org/show_bug.cgi?id=35903
    Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>
    Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Humbly-acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    Signed-off-by: Keith Packard <keithp@keithp.com>

Comment 10 Sitsofe Wheeler 2011-04-13 08:49:16 UTC

A quick note in case anyone arrives at this bug report via the reference link in the commit - the commit id 7f58aabc369014fda3a4a33604ba0a1b63b941ac is incorrect and is not the clean up commit that introduced the problem! It should have been 9db4a9c7b2a3bd5b4952846bc0c2f58daa80ddd7 ...

Sorry!

Comment 11 Chris Wilson 2011-04-13 08:51:31 UTC

/me mutters the one I had in my tree had the corrected changelogs...

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