| Message ID | fae9ee4b-6b93-95ac-abf3-f97c62e07b9d@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmc: core: improve fallback in mmc_select_timing() | expand |
On Fri, 18 Feb 2022 at 08:00, Heiner Kallweit <hkallweit1@gmail.com> wrote: > > I have a system (cheap Amlogic S905W based TV box) where the eMMC chip > refuses to switch to HS200 timing. That's not nice, but my bigger > problem is that the system then falls back to the very slow default > mode, even though DDR52 is supported and works well. > > Therefore, if setting a mode fails with EBADMSG (switch error), try the > next (in descending performance order) mode instead of immediately > falling back to the slowest mode. > > With the patch it looks like this on my system: > > mmc1: mmc_select_hs200 failed, error -74 > mmc1: new DDR MMC card at address 0001 > mmcblk1: mmc1:0001 DG4008 7.28 GiB > Overall, I think the approach seems very much reasonable! Although, I want to have a closer look at the impact on the different scenarios, as mmc_select_timing() is being called during power management and reset too. Allow me a day or so, then I will get back to this, either with some more detailed suggestions or I may post a patch. Kind regards Uffe > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > --- > drivers/mmc/core/mmc.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index bbbbcaf70..c0272192d 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -1523,11 +1523,23 @@ static int mmc_select_timing(struct mmc_card *card) > if (!mmc_can_ext_csd(card)) > goto bus_speed; > > - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) > + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) { > err = mmc_select_hs400es(card); > - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) > + if (!err) > + goto bus_speed; > + if (err != -EBADMSG) > + return err; > + } > + > + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) { > err = mmc_select_hs200(card); > - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) > + if (!err) > + goto bus_speed; > + if (err != -EBADMSG) > + return err; > + } > + > + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) > err = mmc_select_hs(card); > > if (err && err != -EBADMSG) > -- > 2.35.1 >
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index bbbbcaf70..c0272192d 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1523,11 +1523,23 @@ static int mmc_select_timing(struct mmc_card *card) if (!mmc_can_ext_csd(card)) goto bus_speed; - if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES) { err = mmc_select_hs400es(card); - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) + if (!err) + goto bus_speed; + if (err != -EBADMSG) + return err; + } + + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200) { err = mmc_select_hs200(card); - else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) + if (!err) + goto bus_speed; + if (err != -EBADMSG) + return err; + } + + if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS) err = mmc_select_hs(card); if (err && err != -EBADMSG)
I have a system (cheap Amlogic S905W based TV box) where the eMMC chip refuses to switch to HS200 timing. That's not nice, but my bigger problem is that the system then falls back to the very slow default mode, even though DDR52 is supported and works well. Therefore, if setting a mode fails with EBADMSG (switch error), try the next (in descending performance order) mode instead of immediately falling back to the slowest mode. With the patch it looks like this on my system: mmc1: mmc_select_hs200 failed, error -74 mmc1: new DDR MMC card at address 0001 mmcblk1: mmc1:0001 DG4008 7.28 GiB Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- drivers/mmc/core/mmc.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)