Messages in this thread | | | Date | Tue, 21 Jul 2009 19:55:09 +0100 | From | Matt Fleming <> | Subject | Re: Restoring back the system state from MMC after a successful hibernation |
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On Tue, Jul 21, 2009 at 07:35:55PM +0530, A, Raghu wrote: > Hi, > > I am trying a hibernate-restore procedure on my system, wherein I store the context image on a swap partition on a MMC device (/dev/mmcblk0). The hibernation process happens smoothly. However, when I try to restore back, after including "resume = /dev/mmcblk0" in the bootargs, I find that the MMC card does not get detected by the time late_initcall(software_resume) is called, as a result of which the restore does not happen. > > To resolve the problem, I have included a mmc_flush_scheduled_work() call immediately after the mmc_detect_change(host, 0) call in mmc_start_host(struct mmc_host *host) function defined in linux/drivers/mmc/core/core.c, so that instead of mmc_rescan happening sometime later, it now happens right away, and the MMC card gets detected at the end of the host's .probe() callback itself. > > /***** > > void mmc_start_host(struct mmc_host *host) > > { > mmc_power_off(host); > mmc_detect_change(host, 0); > mmc_flush_scheduled_work(); > } > > The host's probe() routine calls mmc_add_host , which in turn calls mmc_start_host. > > *****/ > > Is this approach correct? Or is there any other way I can get the MMC card detected before late_initcall(software_resume) happens? >
I think this is a good idea. Based on the comment for mmc_add_host(), by the time we've exited mmc_add_host() the host should be ready to start servicing requests, so mmc_start_host() really needs to have the detected the card by the time it returns.
Perhaps it would be a good idea for mmc_detect_change() to grow another argument that allows the detection to be synchronous?
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