Re: How to get SDA/SCL bit position in the control word register of the video card?

Vojtech Pavlik
2005-11-24T10:54:07Z

On Thu, Nov 24, 2005 at 10:45:14AM +0000, Vishal Linux wrote:
> Hello,
>
>
> I am trying to communicate to the monitor eeprom to get the monitor
> capabilities and for that i need to have SDA/SCL bit positions in the
> control word register of the video card (to read and wrtie data using
> i2c protocol).
>
> Different video card vendors have different offsets for the control
> word register and different bit positions for SDA/SCL.
>
> I tried to use linux kernel API char* get_EDID_from_BIOS(void*) and
> then using kgdb to debug the kernel module (that i wrote) to get the
> same but failed to find the way to get the above.
>
> I do have the offset of the control word register and Masking Value of
> Intel and Matrox card but i would like NOT to hardcode the masking
> value and the offset in my code. This will lead me to modify my code
> for the different cards.
>
> Is there any way to get the control word register's address (and then
> SDA/SCL bit position) on the linux operating system. Is this
> information available to linux kernel ?
>
> FYI : Masking Value that i am referring to is the value that has to be
> ANDed to the DATA(bit - 0/1) before writing it to Control word
> register so that the right bit can be written on to the SDA/SCL lines.
>
> Any pointers to this or your guidance would be highly appreciated.

No, it's not possible. That's why Linux has to resort to using the BIOS
for this - only the specific BIOS knows how the manufacturer wired the
card.

--
Vojtech Pavlik
SuSE Labs, SuSE CR