Messages in this thread | | | Date | Wed, 12 Feb 2014 11:39:23 +0800 | From | Roger <> | Subject | Re: [PATCH v3 2/3] mmc: Add realtek USB sdmmc host driver |
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On 02/11/2014 05:50 PM, Ulf Hansson wrote: > On 11 February 2014 10:27, Roger <rogerable@realtek.com> wrote: >> On 02/10/2014 10:58 PM, Ulf Hansson wrote: >>> >>> On 6 February 2014 15:35, <rogerable@realtek.com> wrote: >>>> >>>> From: Roger Tseng <rogerable@realtek.com> >>>> >>>> Realtek USB SD/MMC host driver provides mmc host support based on the >>>> Realtek >>>> USB card reader MFD driver. >>>> >>>> Signed-off-by: Roger Tseng <rogerable@realtek.com> >>>> --- >>>> drivers/mmc/host/Kconfig | 7 + >>>> drivers/mmc/host/Makefile | 1 + >>>> drivers/mmc/host/rtsx_usb_sdmmc.c | 1500 >>>> +++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 1508 insertions(+) >>>> create mode 100644 drivers/mmc/host/rtsx_usb_sdmmc.c >> >> [snip] >> >>>> +#ifdef CONFIG_PM_RUNTIME >>> >>> >>> There are stubs for pm_runtime* functions, thus the ifdefs can be removed. >>> Please go though the complete patch and remove all instances. >>> >>>> + pm_runtime_put(sdmmc_dev(host)); >>> >>> >>> I don't know so much about USB mmc hosts hardware, but I just wanted >>> to find out if I have understood this correct. >>> >>> You can't do fine grained power management of the USB parent device, >>> since it needs to be runtime resumed to be able keep the power the >>> card? Once it becomes runtime suspended, the power to the card will >>> thus also be dropped? >>> >> Yes, and to keep some internal state of the controller. > > Okay. > > But the internal state of the controller should be possible to restore > at runtime_resume, so that should not be the reason, right? >
I checked again. Internal registers will hold its state during suspend. Card power is the exact reason. >>> Kind regards >>> Ulf Hansson > . >
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