They have different function, Kevin's patch is for slowly removed, it can't resolve the performance issue. First, we should use get_cd to get the card status, if it is not supported, then use the alive to send CMD13. For the driver that supports get_cd, the system performance can upgrade. Maybe Kevin can base on this patch. Best Regards Jerry Huang > -----Original Message----- > From: Ulf Hansson [mailto:ulf.hansson@xxxxxxxxxx] > Sent: Wednesday, March 20, 2013 4:43 PM > To: Huang Changming-R66093 > Cc: linux-mmc@xxxxxxxxxxxxxxx; Chris Ball > Subject: Re: [PATCH 1/3i v6] MMC/SD: Add callback function to detect card > > On 20 March 2013 06:41, <Chang-Ming.Huang@xxxxxxxxxxxxx> wrote: > > From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx> > > > > In order to check whether the card has been removed, the function > > mmc_send_status() will send command CMD13 to card and ask the card to > > send its status register to sdhc driver, which will generate many > > interrupts repeatedly and make the system performance bad. > > From the performance test on Freescale's board (such as Iozone for > > SD), the performance will degrade about 4~6%. > > > > There is one another way to get this information, which is to read the > > register PRSSTAT and check the bit CDPL or CINS. > > If the card is present, these two bit will set to one. > > Therefore, add callback function get_cd() to check whether the card > > has been inserted/removed when the driver supports this feature. > > If the card is present, 0 will return, if the card is absent, 1 will > return. > > If the controller will not support this feature, -ENOSYS will return. > > > > Signed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx> > > Reviewed-by: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx> > > Reviewed-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx> > > CC: Chris Ball <cjb@xxxxxxxxxx> > > --- > > changes for v2: > > - when controller don't support get_cd, return -ENOSYS > > - add the CC > > changes for v3: > > - enalbe the controller clock in platform, instead of core > > changes for v4: > > - move the detect code to core.c according to the new > > structure changes for v5: > > - reviewed by Anton and Johan, add the reviewed-by. > > changes for v6: > > - add more comment. > > > > drivers/mmc/core/core.c | 16 ++++++++++++++-- > > 1 file changed, 14 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index > > 08a3cf2..e225deb 100644 > > --- a/drivers/mmc/core/core.c > > +++ b/drivers/mmc/core/core.c > > @@ -2280,7 +2280,7 @@ static int mmc_rescan_try_freq(struct mmc_host > > *host, unsigned freq) > > > > int _mmc_detect_card_removed(struct mmc_host *host) { > > - int ret; > > + int ret = -ENOSYS; > > > > if ((host->caps & MMC_CAP_NONREMOVABLE) || !host->bus_ops- > >alive) > > return 0; > > @@ -2288,7 +2288,19 @@ int _mmc_detect_card_removed(struct mmc_host > *host) > > if (!host->card || mmc_card_removed(host->card)) > > return 1; > > > > - ret = host->bus_ops->alive(host); > > + /* First, try host-controller's card detect callback */ > > + if (host->ops->get_cd) { > > + ret = host->ops->get_cd(host); > > + /* > > + * The return value from get_cd: 1 for present, 0 for > absent, > > + * we need to convert it to: 1 for absent, 0 for > present. > > + */ > > + if (ret >= 0) > > + ret = !ret; > > + } > > + /* If failed, back to the bus_ops alive() callback */ > > + if (ret < 0) > > + ret = host->bus_ops->alive(host); > > if (ret) { > > mmc_card_set_removed(host->card); > > pr_debug("%s: card remove detected\n", > mmc_hostname(host)); > > I guess this already has been fixed by Kevin's patch below. > > http://article.gmane.org/gmane.linux.kernel.mmc/19481 > > > -- > > 1.7.9.5 > > > > > > -- > > 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 > > Kind regards > Ulf Hansson -- 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
