# Screen flickering with xf86-video-intel



## sickboy (Feb 7, 2012)

Hi,

I've a problem with Xorg, xf86-video-intel and SDL. I'm running FreeBSD 9.0-STABLE on a desktop machine with an Acer S221HQLBD monitor (1920x1080 @ 60 Hz; connected via DVI).

Everything is fine until I start an SDL application like DOSBox oder OpenTTD. The screen starts "flickering" (short horizontal lines appear occasionally on the screen). About 30 seconds later the monitor turns off and then on right after.

It seems SDL runs with a different monitor frequency or something and my Acer can't handle it. I guess it has something do to with the xf86-video-intel driver. If I use the VESA driver in my xorg.conf instead and running an SDL application the flickering is gone.

Any suggestions?

Excerpt of my xorg.conf:

```
Section "Monitor"
	Identifier   "Monitor0"
	VendorName   "Acer"
	ModelName    "S221HQLBD"
	Option       "DPMS"
	HorizSync    31-83
	VertRefresh  56-76
	Modeline     "1920x1080" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
EndSection

Section "Device"
        ### Available Driver options are:-
        ### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
        ### <string>: "String", <freq>: "<f> Hz/kHz/MHz"
        ### [arg]: arg optional
        #Option     "ShadowFB"           	# [<bool>]
        #Option     "DefaultRefresh"     	# [<bool>]
        #Option     "ModeSetClearScreen" 	# [<bool>]
	Identifier  "Card0"
	Driver      "intel"
#	Driver      "vesa"
	VendorName  "Intel Corporation"
	BoardName   "82Q963/Q965 Integrated Graphics Controller"
	BusID       "PCI:0:2:0"
#	Option      "Monitor0" "TMDS-1"
	Option      "Monitor-TMDS-1" "Monitor0"
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "Card0"
	Monitor    "Monitor0"
	DefaultDepth	24
	SubSection "Display"
		Depth      24
		Modes      "1920x1080"
	EndSubSection
```
]
        #Option


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## SirDice (Feb 8, 2012)

sickboy said:
			
		

> ```
> HorizSync    31-83
> VertRefresh  56-76
> Modeline     "1920x1080" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
> ```


Try removing these. They're usually not needed as EDID will figure out what your monitor is capable of.


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## sickboy (Feb 9, 2012)

Actually this doesn't work, since Xorg can't recognize the full screen resolution of 1920x1080. Nevertheless, I still have screen flickering, which is why I guess it has something to do with xf86-video-intel (but I'm not sure about this).


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## davidgurvich (Feb 9, 2012)

I believe the maximum supported resolution of the graphics card is 1600x1200 at 24 bits.  You could try a lower display depth or lower resolution like 1600x900.


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## sickboy (Feb 10, 2012)

davidgurvich said:
			
		

> I believe the maximum supported resolution of the graphics card is 1600x1200 at 24 bits.  You could try a lower display depth or lower resolution like 1600x900.


For this reason I'm running 915resolution and 1920x1080 works just fine when I use it together with xf86-video-intel. I've never heard that someone has a similar problem with screen flickering while running SDL applications or media players. Are there any other possibilities, except of using the VESA driver and a lower resolution?


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