RE: [PATCH v2] sdio: skip initialization on powered resume

[Bing Zhao <bzhao@marvell.com>]

> -----Original Message-----
> From: Nicolas Pitre [mailto:nico@fluxnic.net]
> Sent: Friday, January 21, 2011 6:56 PM
> To: Bing Zhao
> Cc: zhangfei gao; Sahitya Tummala; linux-mmc@vger.kernel.org; Michal Miroslaw; Chris Ball; Andrew
> Morton; Maxim Levitsky
> Subject: RE: [PATCH v2] sdio: skip initialization on powered resume
> 
> On Fri, 21 Jan 2011, Bing Zhao wrote:
> 
> > Hi Zhangfei,
> >
> > > -----Original Message-----
> > > From: zhangfei gao [mailto:zhangfei.gao@gmail.com]
> > > Sent: Friday, January 21, 2011 1:07 AM
> > > To: Nicolas Pitre; Bing Zhao
> > > Cc: Sahitya Tummala; linux-mmc@vger.kernel.org; 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@fluxnic.net> 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
> > > > --
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> > > >
> > >
> > > 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@fluxnic.net>
> 
> Then this could be revisited eventually when more devices are supported
> and a better abstraction to cover their needs could be created.
> 
> 
> Nicolas

Hi Nicolas,

Thanks for ack. I'll resend the patch with extra explanation in commit log.


Hi Chris,

I'll rebase and test the patch based on git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc.git tree. Should I use "master" or "mmc-next" branch?

Thanks,

Bing