| Message ID | 20201015174115.4cf2c19a@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mmc: sdhci: Use Auto CMD Auto Select only when v4_mode is true | expand |
On 15/10/20 12:41 pm, Jisheng Zhang wrote: > sdhci-of-dwcmshc meets an eMMC read performance regression with below > command after commit 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto > Select support"): > > dd if=/dev/mmcblk0 of=/dev/null bs=8192 count=100000 > > Before the commit, the above command gives 120MB/s > After the commit, the above command gives 51.3 MB/s > > So it looks like sdhci-of-dwcmshc expects Version 4 Mode for Auto > CMD Auto Select. Fix the performance degradation by ensuring v4_mode > is true to use Auto CMD Auto Select. > > Fixes: 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto Select support") > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> > --- > Since v1: > - add the performance degradation on sdhci-of-dwcmshc explanation in > commit msg > - add a comment in the code explaining we require Version 4 Mode because some > controllers(e.g sdhci-of-dwcmshc) expect it that way. > > drivers/mmc/host/sdhci.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 592a55a34b58..3561ae8a481a 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1384,9 +1384,11 @@ static inline void sdhci_auto_cmd_select(struct sdhci_host *host, > /* > * In case of Version 4.10 or later, use of 'Auto CMD Auto > * Select' is recommended rather than use of 'Auto CMD12 > - * Enable' or 'Auto CMD23 Enable'. > + * Enable' or 'Auto CMD23 Enable'. We require Version 4 Mode > + * here because some controllers (e.g sdhci-of-dwmshc) expect it. > */ > - if (host->version >= SDHCI_SPEC_410 && (use_cmd12 || use_cmd23)) { > + if (host->version >= SDHCI_SPEC_410 && host->v4_mode && > + (use_cmd12 || use_cmd23)) { > *mode |= SDHCI_TRNS_AUTO_SEL; > > ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2); >
On Thu, 15 Oct 2020 at 11:41, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > > sdhci-of-dwcmshc meets an eMMC read performance regression with below > command after commit 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto > Select support"): > > dd if=/dev/mmcblk0 of=/dev/null bs=8192 count=100000 > > Before the commit, the above command gives 120MB/s > After the commit, the above command gives 51.3 MB/s > > So it looks like sdhci-of-dwcmshc expects Version 4 Mode for Auto > CMD Auto Select. Fix the performance degradation by ensuring v4_mode > is true to use Auto CMD Auto Select. > > Fixes: 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto Select support") > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Applied for fixes and by adding a stable tag, thanks! Kind regards Uffe > --- > Since v1: > - add the performance degradation on sdhci-of-dwcmshc explanation in > commit msg > - add a comment in the code explaining we require Version 4 Mode because some > controllers(e.g sdhci-of-dwcmshc) expect it that way. > > drivers/mmc/host/sdhci.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 592a55a34b58..3561ae8a481a 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1384,9 +1384,11 @@ static inline void sdhci_auto_cmd_select(struct sdhci_host *host, > /* > * In case of Version 4.10 or later, use of 'Auto CMD Auto > * Select' is recommended rather than use of 'Auto CMD12 > - * Enable' or 'Auto CMD23 Enable'. > + * Enable' or 'Auto CMD23 Enable'. We require Version 4 Mode > + * here because some controllers (e.g sdhci-of-dwmshc) expect it. > */ > - if (host->version >= SDHCI_SPEC_410 && (use_cmd12 || use_cmd23)) { > + if (host->version >= SDHCI_SPEC_410 && host->v4_mode && > + (use_cmd12 || use_cmd23)) { > *mode |= SDHCI_TRNS_AUTO_SEL; > > ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2); > -- > 2.28.0 >
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 592a55a34b58..3561ae8a481a 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1384,9 +1384,11 @@ static inline void sdhci_auto_cmd_select(struct sdhci_host *host, /* * In case of Version 4.10 or later, use of 'Auto CMD Auto * Select' is recommended rather than use of 'Auto CMD12 - * Enable' or 'Auto CMD23 Enable'. + * Enable' or 'Auto CMD23 Enable'. We require Version 4 Mode + * here because some controllers (e.g sdhci-of-dwmshc) expect it. */ - if (host->version >= SDHCI_SPEC_410 && (use_cmd12 || use_cmd23)) { + if (host->version >= SDHCI_SPEC_410 && host->v4_mode && + (use_cmd12 || use_cmd23)) { *mode |= SDHCI_TRNS_AUTO_SEL; ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
sdhci-of-dwcmshc meets an eMMC read performance regression with below command after commit 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto Select support"): dd if=/dev/mmcblk0 of=/dev/null bs=8192 count=100000 Before the commit, the above command gives 120MB/s After the commit, the above command gives 51.3 MB/s So it looks like sdhci-of-dwcmshc expects Version 4 Mode for Auto CMD Auto Select. Fix the performance degradation by ensuring v4_mode is true to use Auto CMD Auto Select. Fixes: 427b6514d095 ("mmc: sdhci: Add Auto CMD Auto Select support") Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> --- Since v1: - add the performance degradation on sdhci-of-dwcmshc explanation in commit msg - add a comment in the code explaining we require Version 4 Mode because some controllers(e.g sdhci-of-dwcmshc) expect it that way. drivers/mmc/host/sdhci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)