On 2010-06-18 오후 9:42, Matt Fleming wrote: > On Fri, 18 Jun 2010 13:05:44 +0900, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >> This patch is bug fixed.. >> I think that host->ios.clock(initial clock) will be set lower than 400KHz. >> But in this code, if host->f_min is higher than 400KHz, print warning message and set higher than 400KHz. >> And We use SDHCI_QUIRK_NONSTANDARD_CLOCK..so using get_min_clock function. >> but didn't effect nothing through used get_min_clock function. > > I'm a little confused. What problem are you fixing with this patch? What > issue are you seeing? SDHCI_QUIRK_NONSTANDARD_CLOCK is only for sdhci. > If this is the old "my card won't initialise at 400kHz" chestnut I don't > think a solution has ever been agreed upon. The problem was that while > some cards won't initialise at 400kHz, some controllers will try to > initialise at too low a frequency which causes other problems. > > Sascha Hauer explains the reason for setting ios.clock to 400kHz here, > > http://lkml.org/lkml/2010/1/5/120 > > So I think your patch will cause problems. > > Which driver are you using? The driver should have set the f_min value > to be <= 400kHz. Maybe it is a good idea to set the value of ios.clock > to 400kHz if the driver has set a bogus f_min value, we will at least > have a fighting chance of initialising the card (though I would say that > the driver was broken, but at least core.c will print a warning). > when ios.clock is higher than 400KHz, why not change 400KHz?(if 400KHz seemed like good value) if clock value is higher than 400KHz, i think card can't initialize...maybe when sdhci controller set f_min value(ie, 300KHz), clock changed 400KHz in core.c. just this code purpose to print warning message? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
