Hello
While testing Linux kernel 2.6.30 and the i915 driver, i noticed that
GPIOA is hardwired to be used as the only possible CRTDDC bus.
code snippet from drivers/gpu/drm/i915/intel_crt.c:
441 /* Set up the DDC bus. */
442 intel_output->ddc_bus = intel_i2c_create(dev, GPIOA, "CRTDDC_A");
443 if (!intel_output->ddc_bus) {
Using the VGA BIOS configuration program, the I2C bus used for CRTDDC
can be changed according to HW requirements (especially if a DVI-I
connector is present on the board), so the above restriction brakes all
platforms not using GPIOA as their CRTDDC bus.
The Xorg Intel graphics driver is at least a little bit more flexible by
probing GPIOD + GPIOE as well for possible attached CRT devices, but i'm
not sure if this really sufficient in all cases.
Shouldn't the i915 driver use the information provided by the VBT
("crt_ddc_gmbus_pin" field in the "bdb_general_definitions" block) to
figure out which I2C to use for CRTDDC?
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