On Mon, 2018-02-12 at 12:59 -0800, Guenter Roeck wrote: > On Mon, Feb 12, 2018 at 11:53:36AM +0100, Jean Delvare wrote: > > On Sat, 30 Dec 2017 08:50:58 -0800, Guenter Roeck wrote: > > > The piix4 i2c driver is extremely slow. Replacing msleep() > > > with usleep_range() increases its speed substantially. [] > > > diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c [] > > > @@ -467,13 +467,13 @@ static int piix4_transaction(struct i2c_adapter *piix4_adapter) > > > > > > /* We will always wait for a fraction of a second! (See PIIX4 docs errata) */ > > > if (srvrworks_csb5_delay) /* Extra delay for SERVERWORKS_CSB5 */ > > > - msleep(2); > > > + usleep_range(2000, 2000); usleep_range without a range isn't particularly useful. Perhaps a 100 uSec range would allow better scheduling. usleep_range(2000, 2100);
