Arch Linux

mathew

Member

Registered: 2013-07-09

Posts: 16

[SOLVED] Garbled text artifacts on display 0.1 zaphod multihead intel

I have recently installed Arch on a Macbook Pro Retina 13 inch [11,1]

Because this laptop has such a high pixel density on the laptop screen, I am using a zaphod multihead set up to
give me seperate openbox instances on the laptop and the external monitor, this way I can set the dpi of each screen individually.

Whichever screen I configure to be display 0.1, is displaying garbled text artifacts. Usually the text displays correctly at first, but becomes increasingly corrupted as more text is displayed.

I think the artifacts may be confined to Gtk applications.

When I run a single desktop, either just on the laptop, or across both screens, this does not seem to occur.

Thinking this might be related to issues other people found with a the xf86-video-intel driver which I am using, I implemented the workaround others have used,
which is to add this to xorg.conf

Option 	"AccelMethod" "sna" 
Option "DebugFlushBatches" "on"
Option "DebugFlushCaches" "on"
	Option "DebugWait" "on"

but it doesn't seem to have worked.

my .xinitrc

#!/bin/sh
#
# ~/.xinitrc
#
# Executed by startx (run your window manager from here)

if [ -d /etc/X11/xinit/xinitrc.d ]; then
  for f in /etc/X11/xinit/xinitrc.d/*; do
    [ -x "$f" ] && . "$f"
  done
  unset f
fi

xset +fp /usr/share/kbd/consolefonts
xset +fp /usr/share/fonts/local
xset fp rehash

DISPLAY=:0.1
exec xrandr --output eDP1 --dpi 192 &

#autostart.common starts compton, redshift and tint2
exec openbox --startup "/home/mathew/.config/openbox/autostart.common"&

DISPLAY=:0.0
#exec xrandr --output HDMI1 --dpi 96
exec openbox-session

my xorg.conf

Section "Files"
	ModulePath   "/usr/lib/xorg/modules"
	FontPath     "/usr/share/fonts/misc/"
	FontPath     "/usr/share/fonts/TTF/"
	FontPath     "/usr/share/fonts/OTF/"
	FontPath     "/usr/share/fonts/Type1/"
	FontPath     "/usr/share/fonts/100dpi/"
	FontPath     "/usr/share/fonts/75dpi/"
EndSection

Section "Module"
	Load  "glx"
EndSection

Section "InputDevice"
	Identifier  "Keyboard0"
	Driver      "kbd"
EndSection

Section "InputDevice"
	Identifier  "Mouse0"
	Driver      "mouse"
	Option	    "Protocol" "auto"
	Option	    "Device" "/dev/input/mice"
	Option	    "ZAxisMapping" "4 5 6 7"
EndSection

Section "Device" 
	Identifier 	"Card0" 
	Driver  	"intel"
	BusID 		"PCI:0:2:0" 
	Option "ZaphodHeads" "DP1,HDMI1,DP2,HDMI2" 
	Option 		"AccelMethod" "sna"
	Option "DebugFlushBatches" "on"
	Option "DebugFlushCaches" "on"
	Option "DebugWait" "on"	 
	Screen 0
EndSection 

Section "Device" 
	Identifier "Card1" 
	Driver "intel"
	BusID "PCI:0:2:0" 
	Option 		"ZaphodHeads" "eDP1" 
	Option "AccelMethod" "sna" 
	Option "DebugFlushBatches" "on"
	Option "DebugFlushCaches" "on"
	Option "DebugWait" "on"
	Screen 1
EndSection 

Section "Screen"
	Identifier "Screen0"
	Device     "Card0"
EndSection

Section "Screen"
	Identifier "Screen1"
	Device     "Card1"
EndSection

Section "ServerLayout"
	Identifier 		"default"
	Screen 		"Screen0" 0 0
	Screen 		"Screen1" RightOf "Screen0"
	InputDevice    	"Mouse0" "CorePointer"
	InputDevice    	"Keyboard0" "CoreKeyboard"
EndSection

Has anyone encountered this before, or have suggestions for how I could go about investigating this further?

Last edited by mathew (2014-04-21 09:53:41)

mathew

Member

Registered: 2013-07-09

Posts: 16

Re: [SOLVED] Garbled text artifacts on display 0.1 zaphod multihead intel

this turned out to be a bug in the video driver which is discussed here:

https://bugs.freedesktop.org/show_bug.cgi?id=54707

i've avoided the problem with this patch:

diff -aur xf86-video-intel-2.99.911/src/sna/sna_glyphs.c xf86-video-intel-2.99.911.modified/src/sna/sna_glyphs.c
--- xf86-video-intel-2.99.911/src/sna/sna_glyphs.c	2014-03-13 10:41:22.000000000 +1100
+++ xf86-video-intel-2.99.911.modified/src/sna/sna_glyphs.c	2014-04-21 19:33:52.423389443 +1000
@@ -1147,7 +1147,7 @@
 		}
 
 		memset(pixmap->devPrivate.ptr, 0, pixmap->devKind*height);
-#if HAS_PIXMAN_GLYPHS
+#if HAS_PIXMAN_GLYPHS & 0
 		if (sna->render.glyph_cache) {
 			pixman_glyph_cache_t *cache = sna->render.glyph_cache;
 			pixman_glyph_t stack_glyphs[N_STACK_GLYPHS];

mathew

Member

Registered: 2013-07-09

Posts: 16

Re: [SOLVED] Garbled text artifacts on display 0.1 zaphod multihead intel

the driver has since been updated and the patch should no longer be required