A udelay value of 20 leads to an I2C bus running at only 25 kbps. I2C devices can typically operate faster than this, 50 kbps should be fine for all devices (and compliant devices can always stretch the clock if needed.)
FWIW, the vast majority of framebuffer drivers set udelay to 10 already. So set it to 10 in DRM drivers too, this will make EDID block reads faster. We might even lower the udelay value later if no problem is reported.
Signed-off-by: Jean Delvare jdelvare@suse.de Acked-by: Eugeni Dodonov eugeni.dodonov@intel.com Cc: Dave Airlie airlied@gmail.com Cc: Keith Packard keithp@keithp.com --- Changes since v1: * Split per driver to make merging easier. * Make the subject line more accurate.
drivers/gpu/drm/i915/intel_i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-3.4-rc0.orig/drivers/gpu/drm/i915/intel_i2c.c 2012-03-21 13:43:33.750915151 +0100 +++ linux-3.4-rc0/drivers/gpu/drm/i915/intel_i2c.c 2012-03-21 13:44:05.923915628 +0100 @@ -37,7 +37,7 @@
/* Intel GPIO access functions */
-#define I2C_RISEFALL_TIME 20 +#define I2C_RISEFALL_TIME 10
static inline struct intel_gmbus * to_intel_gmbus(struct i2c_adapter *i2c)