On 4 April 2012 12:58, Philip Rakity <prakity@xxxxxxxxxxx> wrote: > > Acked-by: Philip Rakity <prakity@xxxxxxxxxxx> > > On Apr 3, 2012, at 8:46 PM, Nath, Arindam wrote: > >> Hi, >> >> >>> -----Original Message----- >>> From: Chris Ball [mailto:cjb@xxxxxxxxxx] >>> Sent: Tuesday, April 03, 2012 6:12 AM >>> To: Alan Cooper >>> Cc: linux-mmc@xxxxxxxxxxxxxxx; Girish K S; Ulf Hansson; Nath, Arindam; >>> Philip Rakity >>> Subject: Re: [PATCH] mmc: Prevent 1.8V switch for SD hosts that don't >>> support UHS modes. >>> >>> Hi Al, >>> >>> On Mon, Apr 02 2012, Alan Cooper wrote: >>>> Still hoping for comments on the patch. >>> >>> Thanks for the reminder; adding a few potential reviewers to CC:. >> >> Acked-by: Arindam Nath <arindam.nath@xxxxxxx> >> >> Regards, >> Arindam >> >>> >>> - Chris. >>> >>>> On Fri, Mar 16, 2012 at 3:54 PM, Al Cooper <acooper@xxxxxxxxx> wrote: >>>>> The driver should not try to switch to 1.8V when the SD 3.0 host >>>>> controller does not have any UHS capabilities bits set (SDR50, DDR50 >>>>> or SDR104). See page 72 of "SD Specifications Part A2 SD Host >>>>> Controller Simplified Specification Version 3.00" under >>>>> "1.8V Signaling Enable". Instead of setting SDR12 and SDR25 in the >>> host >>>>> capabilities data structure for all V3.0 host controllers, only set >>> them >>>>> if SDR104, SDR50 or DDR50 is set in the host capabilities register. >>> This >>>>> will prevent the switch to 1.8V later. >>>>> >>>>> Signed-off-by: Al Cooper <acooper@xxxxxxxxx> >>>>> --- >>>>> drivers/mmc/host/sdhci.c | 5 +++-- >>>>> 1 files changed, 3 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>>>> index 8d66706..cdf900e 100644 >>>>> --- a/drivers/mmc/host/sdhci.c >>>>> +++ b/drivers/mmc/host/sdhci.c >>>>> @@ -2762,8 +2762,9 @@ int sdhci_add_host(struct sdhci_host *host) >>>>> mmc_card_is_removable(mmc)) >>>>> mmc->caps |= MMC_CAP_NEEDS_POLL; >>>>> >>>>> - /* UHS-I mode(s) supported by the host controller. */ >>>>> - if (host->version >= SDHCI_SPEC_300) >>>>> + /* Any UHS-I mode in caps implies SDR12 and SDR25 support. >>> */ >>>>> + if (caps[1] & (SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 | >>>>> + SDHCI_SUPPORT_DDR50)) >>>>> mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25; >>>>> >>>>> /* SDR104 supports also implies SDR50 support */ Cross checked with spec. Acked By: Girish K S <girish.shivananjappa@xxxxxxxxxx> >>>>> -- >>>>> 1.7.6 >>> >>> -- >>> Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> >>> One Laptop Per Child >> > -- 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
