| Message ID | 1426874420-25103-1-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Doug, On Fri, Mar 20, 2015 at 11:30 PM, Doug Anderson <dianders@chromium.org> wrote: > We've already seen that it causes failures if we try to send the > "SDMMC_CMD_UPD_CLK" command when power is off to the system. Here's > another case where we were doing it: we were sending an > SDMMC_CMD_UPD_CLK to set the clock to 0 when the card was already > powered off and the clock was already at 0. Let's avoid that command > and avoid problems. > > Signed-off-by: Doug Anderson <dianders@chromium.org> > --- > drivers/mmc/host/dw_mmc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 47dfd0e..aeec698 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1172,8 +1172,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > > break; > case MMC_POWER_OFF: > - /* Turn clock off before power goes down */ > - dw_mci_setup_bus(slot, false); > + /* Turn clock off before power goes down; only if powered */ > + if (slot->host->vqmmc_enabled) > + dw_mci_setup_bus(slot, false); > vqmmc_enabled is always _true_ when entering MMC_POWER_OFF case..right? Is this done for extra protection? Or do you have a case where vqmmc is OFF and driver still calls dw_mci_setup_bus from here? > if (!IS_ERR(mmc->supply.vmmc)) > mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0); > -- > 2.2.0.rc0.207.ga3a616c > > -- > 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
Alim, On Sun, Mar 22, 2015 at 5:16 AM, Alim Akhtar <alim.akhtar@gmail.com> wrote: >> case MMC_POWER_OFF: >> - /* Turn clock off before power goes down */ >> - dw_mci_setup_bus(slot, false); >> + /* Turn clock off before power goes down; only if powered */ >> + if (slot->host->vqmmc_enabled) >> + dw_mci_setup_bus(slot, false); >> > vqmmc_enabled is always _true_ when entering MMC_POWER_OFF case..right? > Is this done for extra protection? Or do you have a case where vqmmc > is OFF and driver still calls dw_mci_setup_bus from here? Hmm. I know I got it into the debugger in at least one reboot case where it was failing to turn the clock off. I thought I confirmed it was the core trying to call MMC_POWER_OFF when the power was already off, but now I'm less certain. I looked back at my debug session and I don't see where I got that evidence. :-/ Certainly if I put a printout here right now I can't see my code making a difference. Unfortunately the crash was a very rare one, so I may have to go back to the drawing board here... -Doug
Hi, On 03/23/2015 06:59 AM, Doug Anderson wrote: > Alim, > > On Sun, Mar 22, 2015 at 5:16 AM, Alim Akhtar <alim.akhtar@gmail.com> wrote: >>> case MMC_POWER_OFF: >>> - /* Turn clock off before power goes down */ >>> - dw_mci_setup_bus(slot, false); >>> + /* Turn clock off before power goes down; only if powered */ >>> + if (slot->host->vqmmc_enabled) >>> + dw_mci_setup_bus(slot, false); >>> >> vqmmc_enabled is always _true_ when entering MMC_POWER_OFF case..right? >> Is this done for extra protection? Or do you have a case where vqmmc >> is OFF and driver still calls dw_mci_setup_bus from here? > > Hmm. I know I got it into the debugger in at least one reboot case > where it was failing to turn the clock off. I thought I confirmed it > was the core trying to call MMC_POWER_OFF when the power was already > off, but now I'm less certain. I looked back at my debug session and > I don't see where I got that evidence. :-/ Certainly if I put a > printout here right now I can't see my code making a difference. I'm not sure this is really needs...and i can't find any error case.. Best Regards, Jaehoon Chung > > Unfortunately the crash was a very rare one, so I may have to go back > to the drawing board here... > > -Doug >
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 47dfd0e..aeec698 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1172,8 +1172,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) break; case MMC_POWER_OFF: - /* Turn clock off before power goes down */ - dw_mci_setup_bus(slot, false); + /* Turn clock off before power goes down; only if powered */ + if (slot->host->vqmmc_enabled) + dw_mci_setup_bus(slot, false); if (!IS_ERR(mmc->supply.vmmc)) mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
We've already seen that it causes failures if we try to send the "SDMMC_CMD_UPD_CLK" command when power is off to the system. Here's another case where we were doing it: we were sending an SDMMC_CMD_UPD_CLK to set the clock to 0 when the card was already powered off and the clock was already at 0. Let's avoid that command and avoid problems. Signed-off-by: Doug Anderson <dianders@chromium.org> --- drivers/mmc/host/dw_mmc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)