On Fri, 21 Jan 2011, Bing Zhao wrote: > Hi Zhangfei, > > > -----Original Message----- > > From: zhangfei gao [mailto:zhangfei.gao@xxxxxxxxx] > > Sent: Friday, January 21, 2011 1:07 AM > > To: Nicolas Pitre; Bing Zhao > > Cc: Sahitya Tummala; linux-mmc@xxxxxxxxxxxxxxx; Michal Miroslaw; Chris Ball; Andrew Morton; Maxim > > Levitsky > > Subject: Re: [PATCH v2] sdio: skip initialization on powered resume > > > > On Wed, Sep 15, 2010 at 10:26 PM, Nicolas Pitre <nico@xxxxxxxxxxx> wrote: > > > On Wed, 15 Sep 2010, Bing Zhao wrote: > > > > > >> If CMD7 is sent _before_ client driver's resume handler is called, > > >> while 8686 card is in sleep mode, it will fail. If CMD7 is sent > > >> _after_ client driver's resume handler is called, it should succeed. > > > > > > Maybe that's what we should do in the powered suspend case then. > > > > > >> By the way, a patch "mmc: fix all hangs related to mmc/sd card > > >> insert/removal during suspend/resume" > > >> (4c2ef25fe0b847d2ae818f74758ddb0be1c27d8e by Maxim Levitsky) has > > >> removed the call to mmc_detect_change() in mmc_resume_host(). > > > > > > If a card is removed while the host is suspended, then this should be > > > detected. > > > > > > > > > Nicolas > > > -- > > > 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 > > > > > > > Hi, Bing > > > > Do you have any updated patch to skip mmc_sdio_init_card in resume back. > > We need such patch in enable host sleep feature for mrvl8787. > > I posted a patch that skips mmc_sdio_init_card() with MMC_PM_SKIP_RESUME_PROBE flag earlier: > > [PATCH v1] sdio: add MMC_PM_SKIP_RESUME_PROBE to workaround powered resume > http://marc.info/?l=linux-mmc&m=128294262424567&w=2 > > Nicolas commented that it's too hackish with this approach. > http://marc.info/?l=linux-mmc&m=128294738230151&w=2 > > Other than that, I couldn't think of a better way to solve the issue here: > > In mmc_sdio_init_card() CIS device/vendor IDs are read to check if the > card has been replaced or not when the system was suspended. But > reading these IDs will cause CMD52 timeout if the card is in sleep > state. The function driver can wake up the card by writing to certain > card specific register, so that the followed SDIO commands (CMD52, > CMD53, etc.) can go through. But the resume handler of the function > driver won't be invoked until the IDs get validated. Please add the extra explanation above to the commit log so that the context is not lost. And then Acked-by: Nicolas Pitre <nico@xxxxxxxxxxx> Then this could be revisited eventually when more devices are supported and a better abstraction to cover their needs could be created. Nicolas
