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From: Greg KH <gregkh@linuxfoundation.org>
To: Dexuan Cui <decui@microsoft.com>
Cc: linux-kernel@vger.kernel.org,
	driverdev-devel@linuxdriverproject.org, plagnioj@jcrosoft.com,
	tomi.valkeinen@ti.com, linux-fbdev@vger.kernel.org,
	olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com,
	kys@microsoft.com, haiyangz@microsoft.com
Subject: Re: [PATCH] video: hyperv: hyperv_fb: refresh the VM screen by force on VM panic
Date: Tue, 24 Jun 2014 09:51:01 -0400	[thread overview]
Message-ID: <20140624135101.GB10115@kroah.com> (raw)
In-Reply-To: <1403569757-2622-1-git-send-email-decui@microsoft.com>

On Tue, Jun 24, 2014 at 08:29:17AM +0800, Dexuan Cui wrote:
> Currently the VSC has no chance to notify the VSP of the dirty rectangle on VM
> panic because the notification work is done in a workqueue, and in panic() the
> kernel typically ends up in an infinite loop, and a typical kernel config has
> CONFIG_PREEMPT_VOLUNTARY=y and CONFIG_PREEMPT is not set, so a context switch
> can't happen in panic() and the workqueue won't have a chance to run. As a
> result, the VM Connection window can't refresh until it's closed and we
> re-connect to the VM.
> 
> We can register a handler on panic_notifier_list: the handler can notify
> the VSC and switch the framebuffer driver to a "synchronous mode", meaning
> the VSC flushes any future framebuffer change to the VSP immediately.
> 
> MS-TFS: 157532

What is this line for?

thanks,

greg k-h

       reply	other threads:[~2014-06-24 13:51 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1403569757-2622-1-git-send-email-decui@microsoft.com>
2014-06-24 13:51 ` Greg KH [this message]
2014-06-24 21:44   ` [PATCH] video: hyperv: hyperv_fb: refresh the VM screen by force on VM panic Dexuan Cui
2014-06-26  3:36     ` Greg KH
2014-06-26  7:45       ` search by phrase a-la "MS-TFS: 157532" -- "has relevance for Hyper-V sysadmins" " Victor Miasnikov
2014-06-26 20:32       ` Dexuan Cui
2014-06-26  1:53 Dexuan Cui

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