selecting modes with xf86-video-intel modesetting

Keith Packard keithp at
Sun Feb 25 02:56:59 PST 2007

On Sun, 2007-02-25 at 11:50 +0100, Frédéric RISS wrote:

> under the title "X not retrieving EDID data" (the above link contains a
> Xorg.log). I'm also using xf86-video-intel modesetting.

Something is probably going wrong with the low-level i2c code which is
driving the DDC bus. There is debugging code for the i2c code which is
compiled-out by default in i830_i2c.c; if you enable that, you can watch
the DDC bus transactions and perhaps we can figure out why DDC is not

Check out line 264 of i830_i2c.c and set I2C_DEBUG to 1 which will dump
piles of fairly hard to interpret data to the log file; that will show
precisely what levels are set and seen on the I2C bus.

keith.packard at
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