Hi Sahitya, > -----Original Message----- > From: Sahitya Tummala [mailto:stummala@xxxxxxxxxxxxxx] > Sent: Tuesday, September 14, 2010 3:16 AM > To: Bing Zhao > Cc: Nicolas Pitre; linux-mmc@xxxxxxxxxxxxxxx; Michal Miroslaw; Chris Ball; Andrew Morton > Subject: RE: [PATCH v2] sdio: skip initialization on powered resume > > Hi Bing, Chris, > > On Tue, 2010-09-07 at 19:10 -0700, Bing Zhao wrote: > > Hi Nicolas, > > > > > -----Original Message----- > > > From: Nicolas Pitre [mailto:nico@xxxxxxxxxxx] > > > Sent: Tuesday, September 07, 2010 6:29 PM > > > To: Bing Zhao > > > Cc: linux-mmc@xxxxxxxxxxxxxxx; Michal Miroslaw; Chris Ball; Andrew Morton > > > Subject: RE: [PATCH v2] sdio: skip initialization on powered resume > > > > > > On Tue, 7 Sep 2010, Bing Zhao wrote: > > > > > > > Thanks for the hint. > > > > > > > > The new patch skips reading CCCR, common CIS, and validation of > > > > vendor/device IDs inside mmc_sdio_init_card() when powered_resume is > > > > not zero. > > > > > > Why do you skip the reading of the CIS and IDs validation? That's > > > basically the main reason for still calling mmc_sdio_init_card(). And > > > that only requires CMD 52 so that should be fine. > > > > While the system is suspended, the SDIO card could be in sleep mode (deep sleep or IEEE Power Save) > as well. Reading CIS or any other CMD52 will fail if the card happens to be in sleep at this moment. > If we skip re-initialization (including CCCR/CIS and IDs validation), mmc_sdio_init_card() returns > success. Then the client driver's resume() handler will be called and the card can be woken up by > client driver. > > In one of your previous patches, "sdio: don't use CMD[357] as part of a > powered SDIO resume", its mentioned that there is an issue with CMD7 in > mmc_sdio_init_card() that is called during SDIO resume on Marvell 8686. > > But in mmc_resume_host(), there is still a call to mmc_detect_change() > which in turn calls mmc_sdio_detect(), thus sending CMD7 to the card. > Does CMD7 to your card succeed after your client driver resume is > called? 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. 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(). Regards, Bing > > Thanks, > Sahitya. > > -- > Sent by a consultant of the Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora > Forum. > -- 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
