Re: [Linux-fbdev-devel] [PATCH] nvidiafb: allow ignoring EDID info

From: Giuseppe Bilotta
Date: Mon Feb 05 2007 - 16:29:08 EST


On 2/5/07, Luca Tettamanti <kronos@xxxxxxxxx> wrote:
get-edid uses the BIOS, while the other two talk directly over the I2C
bus.

Try loading i2c-dev (I2C_CHARDEV); With i2cdump[1] you can read the EDID
block, which resides at address 0x50:

i2cdump N 0x50 (where N is the bus number)

If you are unshure about bus number try with all the available
/dev/i2c-* devices (you may want to unload HW monitor drivers first, so
you don't poke at random stuff).

No luck. i2c-dev and dependencies are loaded
""" lsmod | grep i2c reports """
i2c_i801 7404 0
i2c_isa 5152 0
i2c_piix4 8140 0
i2c_algo_pcf 6180 0
i2c_algo_pca 5380 0
i2c_algo_bit 8424 0
i2c_dev 8548 0
i2c_core 19680 7
i2c_i801,i2c_isa,i2c_piix4,i2c_algo_pcf,i2c_algo_pca,i2c_algo_bit,i2c_dev
""""

There is no such thing as /dev/i2c* UNLESS I load nvidiafb. When I
load that, I get three busses (i2c-0, -1, and -2), but i2cdump N 0x50
gives me a nice tableau of X's all around, for all values of N. This
is using kernel 2.6.18-3 stock Debian kernel. I'll keep trying with
some variations, to see if I can get more sensible information.

--
Giuseppe "Oblomov" Bilotta
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