On Wed, Mar 21, 2012 at 02:29:47PM +0100, Jean Delvare wrote:
> 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@xxxxxxx>
> Acked-by: Eugeni Dodonov <eugeni.dodonov@xxxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxxx>
> Cc: Keith Packard <keithp@xxxxxxxxxx>
Fyi this already got merged int Dave's tree (the unsplit version) as:
commit 1849ecb22fb3b5d57b65e7369a3957adf9f26f39
Author: Jean Delvare <jdelvare@xxxxxxx>
Date: Sat Jan 28 11:07:09 2012 +0100
drm/kms: Make i2c buses faster
Cheers, Daniel
> ---
> 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)
>
> --
> Jean Delvare
> Suse L3
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--
Daniel Vetter
Mail: daniel@xxxxxxxx
Mobile: +41 (0)79 365 57 48
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