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

[James Simmons <jsimmons@infradead.org>]

> On 2/5/07, Luca Tettamanti <kronos@people.it> 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.

There is no stand alone nvidia card i2c driver. Its the issue of sharing 
device interfaces with the same hardware problem again!!! There is a patch 
for DRI and fbdev but it really looks like we need a generic solution.