| Message ID | 4DCB97F3.9060704@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
The required min frequency (f_min) is 400KHz during identify stage, is it necessary to use the frequency table (freqs[], including 300KHz, 200KHz and 100KHz)? Thanks and Best Regards Jerry Huang > -----Original Message----- > From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc- > owner@vger.kernel.org] On Behalf Of Jaehoon Chung > Sent: Thursday, May 12, 2011 4:19 PM > To: linux-mmc@vger.kernel.org > Cc: Chris Ball; Kyungmin Park; andy.ross@windriver.com > Subject: [PATCH] mmc: duplicated trial with same freq when > mmc_rescan_try_freq() > > when running mmc_rescan_try_freq(), try to init two times with last > frequency. > For example, assume that host->f_min is 400KHz, we can find the below > message. > > mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz > mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz > > i didn't find to mention about this..why try to init the two times with > same frequency? > Is there any reason? If i missed the history, plz let me know them. > > I think that trial is not necessary. Trial needs to running with other > frequency. > > Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> > --- > drivers/mmc/core/core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index > 61c6c0b..a330c58 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -1618,7 +1618,7 @@ void mmc_rescan(struct work_struct *work) > for (i = 0; i < ARRAY_SIZE(freqs); i++) { > if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min))) > break; > - if (freqs[i] < host->f_min) > + if (freqs[i] <= host->f_min) > break; > } > mmc_release_host(host); > -- > 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 -- 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
This patch didn't point that.. Huang Changming-R66093 wrote: > The required min frequency (f_min) is 400KHz during identify stage, is it necessary to use the frequency table (freqs[], including 300KHz, 200KHz and 100KHz)? i known that some card needs lower than 400KHz..so this approach is not problem.. But i mentions that try to init two times with same frequency. Regards, Jaehoon Chung > > Thanks and Best Regards > Jerry Huang > > >> -----Original Message----- >> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc- >> owner@vger.kernel.org] On Behalf Of Jaehoon Chung >> Sent: Thursday, May 12, 2011 4:19 PM >> To: linux-mmc@vger.kernel.org >> Cc: Chris Ball; Kyungmin Park; andy.ross@windriver.com >> Subject: [PATCH] mmc: duplicated trial with same freq when >> mmc_rescan_try_freq() >> >> when running mmc_rescan_try_freq(), try to init two times with last >> frequency. >> For example, assume that host->f_min is 400KHz, we can find the below >> message. >> >> mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz >> mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz >> >> i didn't find to mention about this..why try to init the two times with >> same frequency? >> Is there any reason? If i missed the history, plz let me know them. >> >> I think that trial is not necessary. Trial needs to running with other >> frequency. >> >> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> >> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> >> --- >> drivers/mmc/core/core.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index >> 61c6c0b..a330c58 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -1618,7 +1618,7 @@ void mmc_rescan(struct work_struct *work) >> for (i = 0; i < ARRAY_SIZE(freqs); i++) { >> if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min))) >> break; >> - if (freqs[i] < host->f_min) >> + if (freqs[i] <= host->f_min) >> break; >> } >> mmc_release_host(host); >> -- >> 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 > > > -- > 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 > -- 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
Hi, On Thu, May 12 2011, Huang Changming-R66093 wrote: > The required min frequency (f_min) is 400KHz during identify stage, is > it necessary to use the frequency table (freqs[], including 300KHz, > 200KHz and 100KHz)? Yes. Some hardware is buggy/out of compliance with the spec. - Chris.
Hi Chris.. My question is others..I agreed the using frequency table.. But my questions is this... For example, if f_min is 300KHz, you can the below message. mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz mmc1: mmc_rescan_try_freq: trying to init card at 300000 Hz mmc1: mmc_rescan_try_freq: trying to init card at 300000 Hz In other words, first init card with 400KHZ, but second/third to init with 300KHz. i think not necessary that try to initialize the two times with 300KHz. I want to know your opinion.. Regards, Jaehoon Chung Chris Ball wrote: > Hi, > > On Thu, May 12 2011, Huang Changming-R66093 wrote: >> The required min frequency (f_min) is 400KHz during identify stage, is >> it necessary to use the frequency table (freqs[], including 300KHz, >> 200KHz and 100KHz)? > > Yes. Some hardware is buggy/out of compliance with the spec. > > - Chris. -- 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
On 05/12/2011 07:16 PM, Jaehoon Chung wrote: > In other words, first init card with 400KHZ, > but second/third to init with 300KHz. > i think not necessary that try to initialize the two times with 300KHz. This sounds like a correct patch to me. Presumably the board I was using had a f_min that didn't match one of the table entries exactly, so I didn't see the mixed up equality condition. Unfortunately that board is gone now, so I can't test. But the logic looks fine. Andy -- 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
Hi Jaehoon, On Thu, May 12 2011, Jaehoon Chung wrote: > when running mmc_rescan_try_freq(), try to init two times with last frequency. > For example, assume that host->f_min is 400KHz, we can find the below message. > > mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz > mmc1: mmc_rescan_try_freq: trying to init card at 400000 Hz > > i didn't find to mention about this..why try to init the two times with same frequency? > Is there any reason? If i missed the history, plz let me know them. > > I think that trial is not necessary. Trial needs to running with other frequency. > > Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> > --- > drivers/mmc/core/core.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 61c6c0b..a330c58 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -1618,7 +1618,7 @@ void mmc_rescan(struct work_struct *work) > for (i = 0; i < ARRAY_SIZE(freqs); i++) { > if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min))) > break; > - if (freqs[i] < host->f_min) > + if (freqs[i] <= host->f_min) > break; > } > mmc_release_host(host); > Thanks, merged to mmc-next for .40. - Chris.
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 61c6c0b..a330c58 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1618,7 +1618,7 @@ void mmc_rescan(struct work_struct *work) for (i = 0; i < ARRAY_SIZE(freqs); i++) { if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min))) break; - if (freqs[i] < host->f_min) + if (freqs[i] <= host->f_min) break; } mmc_release_host(host);