Comment 0 for bug 311895

I am using a Dell Latitude D430 with an Intel GM945.

When I use my external 19" TFT (through DVI, 1280x1024), I occasionally get a black screen. This is not triggered by anything obvious, it just happens spontaneously. It is impossible to recover from this with restarting X, only a reboot cures it.

Further investigation shows that this is caused by a long series of

  (EE) intel(0): underrun on pipe A!

errors (some 10.000 lines in the log). I get short underruns pretty often, which results in the screen flickering for a split second, but when the long series happens, the screen stays black forever.

A comparison of the intel_reg_dump output (-: works, +: black screen) confirms this as well:

-(II): PIPEASTAT: 0x00000203 (status: VSYNC_INT_STATUS VBLANK_INT_STATUS OREG_UPDATE_STATUS)
+(II): PIPEASTAT: 0x80000000 (status: FIFO_UNDERRUN)

I have not observed this behaviour when I use the laptop undocked, with the internal screen (1280x800).

This is current Ubuntu Jaunty with -intel 2.5.1, X.org server 1.5.3, kernel 2.6.28. It also happened with earlier releases.