linux-kernel - Re: [PATCH] mmc: omap_hsmmc: Pass on the suspend failure to the PM core

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Date:	Tue, 11 Sep 2012 11:13:26 +0530
From:	"S, Venkatraman" <svenkatr@...com>
To:	"Hebbar, Gururaja" <gururaja.hebbar@...com>
Cc:	linux-omap@...r.kernel.org, linux-mmc@...r.kernel.org,
	rob.herring@...xeda.com, linux-kernel@...r.kernel.org,
	grant.likely@...retlab.ca, cjb@...top.org, nsekhar@...com,
	sudhakar.raj@...com, Vaibhav Bedia <vaibhav.bedia@...com>
Subject: Re: [PATCH] mmc: omap_hsmmc: Pass on the suspend failure to the PM core

On Tue, Sep 4, 2012 at 6:38 PM, Hebbar, Gururaja <gururaja.hebbar@...com> wrote:
> From: Vaibhav Bedia <vaibhav.bedia@...com>
>
> In some cases mmc_suspend_host() is not able to claim the
> host and proceed with the suspend process. The core returns
> -EBUSY to the host controller driver. Unfortunately, the
> host controller driver does not pass on this information
> to the PM core and hence the system suspend process continues.
>
> In these cases the MMC core gets to an unexpected state
> during resume and multiple issues related to MMC crop up.
> 1. Host controller driver starts accessing the device registers
> before the clocks are enabled which leads to a prefetch abort.
> 2. A file copy thread which was launched before suspend gets
> stuck due to the host not being reclaimed during resume.
>
> To avoid such problems pass on the -EBUSY status to the PM core
> from the host controller driver. With this change, MMC core
> suspend might still fail but it does not end up making the
> system unusable. Suspend gets aborted and the user can try
> suspending the system again.
>

The last time we discussed this, didn't we plan to fix this differently ?
Holding the return code of mmc_suspend_host in a separate variable and
passing it to the caller
of omap_hsmmc_suspend looks more sane to me.
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