Hi Ulf,
I see similar issue with your patch in 3.2 "mmc: core: Prevent too long
response times for suspend".
if (mmc_try_claim_host(host)) {
<snip>
/* if CONFIG_MMC_UNSAFE_RESUME is not set, remove() callback would get
blocked until mmcqd gets mmc_claim_host() causing deadlock here */
if (host->bus_ops->remove)
host->bus_ops->remove(host);
<snip>
} else {
err = -EBUSY;
}
}
Proabably, we can do something like this:
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 5278ffb..0177d4a 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2309,6 +2309,7 @@ int mmc_suspend_host(struct mmc_host *host)
* We simply "remove" the card in this
case.
* It will be redetected on resume.
*/
+ mmc_do_release_host(host);
if (host->bus_ops->remove)
host->bus_ops->remove(host);
mmc_claim_host(host);
@@ -2317,8 +2318,9 @@ int mmc_suspend_host(struct mmc_host *host)
mmc_release_host(host);
host->pm_flags = 0;
err = 0;
+ } else {
+ mmc_do_release_host(host);
}
- mmc_do_release_host(host);
} else {
err = -EBUSY;
}
Please let me know if you agree. I can post a patch for this.
Thanks
Sujit
On 11/15/2011 12:27 PM, Dong, Chuanxiao wrote:
Hi Viresh,
I also meet the hang issue when suspending a system with a mounted SD card. Actually it caused by a dead lock of mmc_claim_host. Maybe we faced the same issue.
So may be the two mails in the attachment can help you.
Thanks
Chuanxiao
-----Original Message-----
From: linux-mmc-owner@xxxxxxxxxxxxxxx
[mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Viresh Kumar
Sent: Tuesday, November 15, 2011 1:47 PM
To: Chris Ball
Cc: linux-mmc@xxxxxxxxxxxxxxx; Shiraz HASHIM; Armando VISCONTI
Subject: Re: [Query] mmc/sdhci: Suspend hangs if card is inserted at suspend.
On 11/12/2011 8:54 AM, Chris Ball wrote:
On Fri, Nov 11 2011, Viresh Kumar wrote:
Controller specific suspend/resume are still not called, so i think it might
be related to core code. I am using 2.6.37 kernel version.
Any help on this?
Please try to reproduce on 3.1 and let us know if it's present there.
Hi Chris,
Support for SPEAr13xx is not present on 3.1 and it will take some time to
move support there. I have a bit more info which might able you to guide us:
file: drivers/mmc/card/queue.c
static int mmc_queue_thread(void *d)
{
...
do {
req = blk_fetch_request(q);
...
if (!req) {
if (kthread_should_stop()) {
set_current_state(TASK_RUNNING);
break;
}
up(&mq->thread_sem);
schedule();
down(&mq->thread_sem);
continue;
}
set_current_state(TASK_RUNNING);
mq->issue_fn(mq, req);
} while (1);
...
}
- In normal cases, i.e. when we are able to stop this thread,
req is returned as NULL from blk_fetch_request()
- Suspend hang only occurs when the card is mounted.
- When suspend hangs, req is not returned as NULL and the card is
already removed by kernel and so we never check kthread_should_stop().
So it hangs.
--
viresh
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--
Thanks & Regards,
Sujit Reddy Thumma
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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