On Wed, 28 Aug 2019 at 03:15, Philip Langdale <philipl@xxxxxxxxx> wrote: > > On Tue, 27 Aug 2019 10:10:43 +0200 > Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > The OCR register defines the supported range of VDD voltages for SD > > cards. However, it has turned out that some SD cards reports an > > invalid voltage range, for example having bit7 set. > > > > When a host supports MMC_CAP2_FULL_PWR_CYCLE and some of the voltages > > from the invalid VDD range, this triggers the core to run a power > > cycle of the card to try to initialize it at the lowest common > > supported voltage. Obviously this fails, since the card can't support > > it. > > > > Let's fix this problem, by clearing invalid bits from the read OCR > > register for SD cards, before proceeding with the VDD voltage > > negotiation. > > > > Cc: stable@xxxxxxxxxxxxxxx > > Reported-by: Philip Langdale <philipl@xxxxxxxxx> > > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > --- > > drivers/mmc/core/sd.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > > index d681e8aaca83..fe914ff5f5d6 100644 > > --- a/drivers/mmc/core/sd.c > > +++ b/drivers/mmc/core/sd.c > > @@ -1292,6 +1292,12 @@ int mmc_attach_sd(struct mmc_host *host) > > goto err; > > } > > > > + /* > > + * Some SD cards claims an out of spec VDD voltage range. > > Let's treat > > + * these bits as being in-valid and especially also bit7. > > + */ > > + ocr &= ~0x7FFF; > > + > > rocr = mmc_select_voltage(host, ocr); > > > > /* > > Looks right. Tried it out and worked as expected. > > Reviewed-by: Philip Langdale <philipl@xxxxxxxxx> Thanks! I add your tested-by tag as well! Kind regards Uffe
