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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Daniel Mack <zonque@gmail.com>
Cc: linux-usb@vger.kernel.org, linux-omap@vger.kernel.org,
	neumann@teufel.de, vinod.koul@intel.com,
	dan.j.williams@intel.com, balbi@ti.com
Subject: Re: [PATCH v2 1/5] usb: musb: move port reset to worker
Date: Wed, 2 Oct 2013 12:46:12 +0200	[thread overview]
Message-ID: <20131002104612.GC16680@linutronix.de> (raw)
In-Reply-To: <1380634797-29541-2-git-send-email-zonque@gmail.com>

* Daniel Mack | 2013-10-01 15:39:53 [+0200]:

>musb_port_reset() sleeps, so we can't call it from atomic context. It
>is, however, called from places inside musb_hub_control() while
>&musb->lock is held, which leads to a "scheduling while atomic" warning.

I guess you are hit by the msleep(1) here.

>Fix this by moving the logic into a worker, and call it where the
>function was previously called directly.

I *think* the better approach here would be to replace the msleep(1) by
a busy loop. The thing is that you do now want to continue the operation
and having the reset in progress. It should complete _right_ _now_ i.e.
SET_PORT_FEATURE RESET is completed before the the next SET/GET request
arrives and with a workqueue you can not guarantee this.

>Signed-off-by: Daniel Mack <zonque@gmail.com>

Sebastian

  reply	other threads:[~2013-10-02 10:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-01 13:39 [PATCH v2 0/5] usb: musb_dsps: support for suspend and resume Daniel Mack
2013-10-01 13:39 ` [PATCH v2 1/5] usb: musb: move port reset to worker Daniel Mack
2013-10-02 10:46   ` Sebastian Andrzej Siewior [this message]
2013-10-02 11:19     ` Daniel Mack
     [not found] ` <1380634797-29541-1-git-send-email-zonque-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-01 13:39   ` [PATCH v2 2/5] usb: musb: call musb_port_suspend from musb_bus_suspend Daniel Mack
2013-10-02 10:49     ` Sebastian Andrzej Siewior
2013-10-02 11:14       ` Daniel Mack
     [not found]         ` <524C001B.8040901-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-02 12:01           ` Sebastian Andrzej Siewior
2013-10-02 12:12             ` Daniel Mack
     [not found]               ` <524C0D94.8050100-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-02 14:52                 ` Alan Stern
2013-10-01 13:39 ` [PATCH v2 3/5] usb: musb: conditionally save and restore the context on suspend Daniel Mack
2013-10-01 13:39 ` [PATCH v2 4/5] usb: musb: dsps: add {tx,rx}_mode to wrapper Daniel Mack
2013-10-01 13:39 ` [PATCH v2 5/5] usb: musb: dsps: add support for suspend and resume Daniel Mack
2013-10-01 14:59   ` Felipe Balbi
2013-10-01 15:04     ` Daniel Mack
     [not found]       ` <524AE464.3020201-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-10-01 16:03         ` Felipe Balbi

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