Hi Philip.. If i didn't set MMC_CAP_BUS_WIDTH_TEST, entered mmc_compare_ext_csds(). right? i understand that mmc_compare_ext_csds() compared with previously ext_csd. But in source code, always previously ext_csd is NULL. I didn't find where assigned ext_csd.. I think that need to assign ext_csd.. If my point is right, i will send the patch.. Thanks Jaehoon Chung Philip Rakity wrote: > On Jun 28, 2011, at 9:42 PM, Jaehoon Chung wrote: > >> Philip Rakity wrote: >>> On Jun 28, 2011, at 3:54 AM, Jaehoon Chung wrote: >>> >>>> Hi.. >>>> >>>> I found the MMC_CAP_BUS_WIDTH_TEST... >>>> In mailing, I read the related patches.. >>>> but i didn't fully understand... >>>> >>>> /* >>>> * If controller can't handle bus width test, >>>> * compare ext_csd previously read in 1 bit mode >>>> * against ext_csd at new bus width >>>> */ >>>> if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST)) >>>> err = mmc_compare_ext_csds(card, >>>> ext_csd, >>>> bus_width); >>>> else >>>> err = mmc_bus_test(card, bus_width); >>>> if (!err) >>>> break; >>>> >>>> And i tested suspend/resume..it's failed.. >>>> If i didn't set MMC_CAP_BUS_WIDTH_TEST, always return -EINVAL.. >>>> (using SDHCI controller, card is eMMC4.41) >>>> >>>> Didn't compare ext_csd's value.. >>>> >>>> So i want to know how use MMC_CAP_BUS_WIDTH_TEST.. >>> I am using eMMC and code works fine so maybe there is issue in no ext_csd. You will need to >>> add debug code to the compare_ext_csd and see what is not right and we can adjust the code. >>> I am surprised that resume fails -- code will default to 1 bit data and it is NOT possible for this to >>> be wrong. At the moment -- clueless to explain with more information. >>> >>> TheCMD14/ CMD19 is in JEDEC spec for bus width testing. Sends a pattern to the card and >>> based on the returned values detects the bus width. Some controllers do NOT support this command. >>> The just do not work. You need to figure this out by enabling the quirk. No other way to know. >> When card is probing, i think that need to test bus-width. >> If card is non-removable, unnecessary bus_width test during resuming. > > agree not necessary but does not explain error. > > >> Because already know that support n-bit bus-width..how about this? >> >>> regards, >>> >>> Philip >>> >>>> Thanks, >>>> Jaehoon Chung >>> -- >>> 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 >>> > > -- > 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 > -- 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
