| Message ID | 20180531094041.27902-1-ulf.hansson@linaro.org |
|---|---|
| Headers | show |
| Series | mmc: rtsx_usb_sdmmc: Don't waste energy polling for cards | expand |
Hi Ulf, > On May 31, 2018, at 5:40 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > > This series re-works the polling mechanism for the rtsx_usb_mmc driver, > which > currently relies on pure polling via MMC_CAP_NEEDS_POLL. The problem is > simply > that is wastes a lot of energy, while in fact the card detection logic > don't > need to use polling. > > Do note, this series doesn't work out of the box, as one addtional patch is > needed on the rtsx USB misc driver (runtime resuming the child at card > detect). > I leave that for Kai Heng Feng to implement and moreover I rely on tests > to be > done, as this series has only been compile tested. After applying this patch series, the rtsx_usb_sdmmc_runtime_{suspend,resume} constantly get called, so the parent device can no longer suspend/resume. Not sure what went wrong here but I'll take a look. Also, what do I need to do to use pm_runtime_idle()? I tried to add an idle function but it never gets called. Kai-Heng > > Kind regards > Uffe > > Ulf Hansson (4): > mmc: core: Introduce MMC_CAP_SYNC_RUNTIME_PM > mmc: rtsx_usb_sdmmc: Don't runtime resume the device while changing > led > mmc: rtsx_usb_sdmmc: Re-work runtime PM support > mmc: rtsx_usb_sdmmc: Re-work card detection/removal support > > drivers/mmc/core/core.c | 5 +++- > drivers/mmc/host/rtsx_usb_sdmmc.c | 43 +++++++++++++++++++++++++------ > include/linux/mmc/host.h | 2 +- > 3 files changed, 40 insertions(+), 10 deletions(-) > > -- > 2.17.0 -- 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 Fri, 1 Jun 2018, Kai Heng Feng wrote: > Hi Ulf, > > > On May 31, 2018, at 5:40 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > > > > This series re-works the polling mechanism for the rtsx_usb_mmc driver, > > which > > currently relies on pure polling via MMC_CAP_NEEDS_POLL. The problem is > > simply > > that is wastes a lot of energy, while in fact the card detection logic > > don't > > need to use polling. > > > > Do note, this series doesn't work out of the box, as one addtional patch is > > needed on the rtsx USB misc driver (runtime resuming the child at card > > detect). > > I leave that for Kai Heng Feng to implement and moreover I rely on tests > > to be > > done, as this series has only been compile tested. > > After applying this patch series, the > rtsx_usb_sdmmc_runtime_{suspend,resume} constantly get called, so the > parent device can no longer suspend/resume. Not sure what went wrong here > but I'll take a look. > > Also, what do I need to do to use pm_runtime_idle()? I tried to add an idle > function but it never gets called. Basically, the PM core calls pm_runtime_idle() when it thinks the driver might want to suspend the device. For example, after pm_runtime_put() runs, the core would call pm_runtime_idle() if the usage counter has dropped to 0. pm_runtime_idle() is optional; if the callback doesn't exist then the PM core will call pm_runtime_suspend(). Alan Stern -- 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 1 June 2018 at 13:00, Kai Heng Feng <kai.heng.feng@canonical.com> wrote: > Hi Ulf, > >> On May 31, 2018, at 5:40 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: >> >> This series re-works the polling mechanism for the rtsx_usb_mmc driver, >> which >> currently relies on pure polling via MMC_CAP_NEEDS_POLL. The problem is >> simply >> that is wastes a lot of energy, while in fact the card detection logic >> don't >> need to use polling. >> >> Do note, this series doesn't work out of the box, as one addtional patch >> is >> needed on the rtsx USB misc driver (runtime resuming the child at card >> detect). >> I leave that for Kai Heng Feng to implement and moreover I rely on tests >> to be >> done, as this series has only been compile tested. > > > After applying this patch series, the > rtsx_usb_sdmmc_runtime_{suspend,resume} constantly get called, so the parent > device can no longer suspend/resume. Not sure what went wrong here but I'll > take a look. Thanks for testing! I realize the problem. The detect work gets scheduled over and over again, even if there is no card inserted. I just posted a v2 of patch 4/4, please try it. [...] Kind regards Uffe -- 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 series re-works the polling mechanism for the rtsx_usb_mmc driver, which currently relies on pure polling via MMC_CAP_NEEDS_POLL. The problem is simply that is wastes a lot of energy, while in fact the card detection logic don't need to use polling. Do note, this series doesn't work out of the box, as one addtional patch is needed on the rtsx USB misc driver (runtime resuming the child at card detect). I leave that for Kai Heng Feng to implement and moreover I rely on tests to be done, as this series has only been compile tested. Kind regards Uffe Ulf Hansson (4): mmc: core: Introduce MMC_CAP_SYNC_RUNTIME_PM mmc: rtsx_usb_sdmmc: Don't runtime resume the device while changing led mmc: rtsx_usb_sdmmc: Re-work runtime PM support mmc: rtsx_usb_sdmmc: Re-work card detection/removal support drivers/mmc/core/core.c | 5 +++- drivers/mmc/host/rtsx_usb_sdmmc.c | 43 +++++++++++++++++++++++++------ include/linux/mmc/host.h | 2 +- 3 files changed, 40 insertions(+), 10 deletions(-) -- 2.17.0