| Message ID | 20170213114641.372-1-anssi.hannula@bitwise.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 13.2.2017 13:46, Anssi Hannula wrote: [...] > Fix the code to allow 4-bit and 8-bit widths even without high-speed > mode, as before. > > Tested with a Zynq-7000 PicoZed 7020 board. > > Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> > Cc: Seungwon Jeon <tgih.jun@samsung.com> FYI, looks like the above CC bounced. > Cc: <stable@vger.kernel.org> > Fixes: 577fb13199b1 ("mmc: rework selection of bus speed mode") > --- > drivers/mmc/core/mmc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index b61b52f9..0fccca0 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -1706,10 +1706,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, > err = mmc_select_hs400(card); > if (err) > goto free_card; > - } else if (mmc_card_hs(card)) { > + } else { > /* Select the desired bus width optionally */ > err = mmc_select_bus_width(card); > - if (err > 0) { > + if (err > 0 && mmc_card_hs(card)) { > err = mmc_select_hs_ddr(card); > if (err) > goto free_card;
- Seungwon (due to bouncing email) On 13 February 2017 at 12:46, Anssi Hannula <anssi.hannula@bitwise.fi> wrote: > Commit 577fb13199b1 ("mmc: rework selection of bus speed mode") > refactored bus width selection code to mmc_select_bus_width(). > > However, it also altered the behavior to not call the selection code in > non-high-speed modes anymore. > > This causes 1-bit mode to always be used when the high-speed mode is not > enabled, even though 4-bit and 8-bit bus are valid bus widths in the > backwards-compatibility (legacy) mode as well (see e.g. 5.3.2 Bus Speed > Modes in JEDEC 84-B50). This results in a significant regression in > transfer speeds. > > Fix the code to allow 4-bit and 8-bit widths even without high-speed > mode, as before. > > Tested with a Zynq-7000 PicoZed 7020 board. > > Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> > Cc: Seungwon Jeon <tgih.jun@samsung.com> > Cc: <stable@vger.kernel.org> > Fixes: 577fb13199b1 ("mmc: rework selection of bus speed mode") Thanks, applied for fixes! Kind regards Uffe > --- > drivers/mmc/core/mmc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index b61b52f9..0fccca0 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -1706,10 +1706,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, > err = mmc_select_hs400(card); > if (err) > goto free_card; > - } else if (mmc_card_hs(card)) { > + } else { > /* Select the desired bus width optionally */ > err = mmc_select_bus_width(card); > - if (err > 0) { > + if (err > 0 && mmc_card_hs(card)) { > err = mmc_select_hs_ddr(card); > if (err) > goto free_card; > -- > 2.8.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index b61b52f9..0fccca0 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1706,10 +1706,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, err = mmc_select_hs400(card); if (err) goto free_card; - } else if (mmc_card_hs(card)) { + } else { /* Select the desired bus width optionally */ err = mmc_select_bus_width(card); - if (err > 0) { + if (err > 0 && mmc_card_hs(card)) { err = mmc_select_hs_ddr(card); if (err) goto free_card;
Commit 577fb13199b1 ("mmc: rework selection of bus speed mode") refactored bus width selection code to mmc_select_bus_width(). However, it also altered the behavior to not call the selection code in non-high-speed modes anymore. This causes 1-bit mode to always be used when the high-speed mode is not enabled, even though 4-bit and 8-bit bus are valid bus widths in the backwards-compatibility (legacy) mode as well (see e.g. 5.3.2 Bus Speed Modes in JEDEC 84-B50). This results in a significant regression in transfer speeds. Fix the code to allow 4-bit and 8-bit widths even without high-speed mode, as before. Tested with a Zynq-7000 PicoZed 7020 board. Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> Cc: Seungwon Jeon <tgih.jun@samsung.com> Cc: <stable@vger.kernel.org> Fixes: 577fb13199b1 ("mmc: rework selection of bus speed mode") --- drivers/mmc/core/mmc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)