29.01.2019 1:15, Sowjanya Komatineni пишет: > > >>>>> Update I2C transfer timeout based on transfer bytes and I2C bus rate >>>>> to allow enough time during max transfer size based on the speed. >>>> >>>> Could it be that I2C device is busy and just slowly handling the transfer >>>> requests? Maybe better to leave the timeout as-is and assume the worst >>>> case scenario? >>>> >>> This change includes min transfer time out of 100ms in addition to computed >>> timeout based on transfer bytes and speed which can account in cases of >>> slave devices running at slower speed. >>> Also Tegra I2C Master supports Clock stretching by the slave. >> >> Okay, I suppose in reality this shouldn't break anything. >> >> Please explain what benefits this change brings. Does it fix or improve >> anything? The commit message only describes changes done in the patch and >> has no word on justification of those changes. Transfer timeout is an >> extreme case that doesn't happen often and > > when it happens, usually only >> the fact of timeout matters. If there is no real value in shortening of the >> timeout, why bother then? > > Original transfer timeout in existing driver is 1Sec and incases of transfer > size more than 10Kbytes at STD bus rate, timeout is not sufficient. > Also Tegra194 platform supports max of 64K bytes of transfer and to allow > full transfer size at lowest bus rate it takes almost ~5.8 Sec. > In cases if large transfer at low bus rates 1 Sec timeout is not enough and > in those cases transfers will timeout before it waits for complete transfer > to happen. > > So this patch uses transfer time based on transfer bytes and bus rate. >
Please add that to the commit message. And then seems you also need to set I2C adapter timeout to a some larger value. Currently Tegra's I2C doesn't explicitly specify the "adapter.timeout" and I2C core sets it to 1 second if it is 0.
