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From: Zhi Wang <zhi.a.wang@intel.com>
To: "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>
Subject: About the wait_for() macro in intel_drv.h
Date: Wed, 15 Jul 2015 22:07:54 +0800	[thread overview]
Message-ID: <55A6693A.1000704@intel.com> (raw)

Hi Gurus:
    Recently we found that the wait_for() marco in intel_drv.h looks
will cause dead lock. wait_for() macro will try to wait jiffies change
in a condition check loop, but when local cpu interrupt is disabled, it
seems the jiffies will never change under a uni-processor environment.
And in forcewake_get/put path, the local cpu irq will always be disabled
by a spin_lock_irqsave() in genX_read() and some genX_write(), So if the
change of HW register (e.g. forcewake ack) turns slow at this time,
there should be a dead lock here I think?

Thanks,
Zhi.
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             reply	other threads:[~2015-07-16  5:40 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-15 14:07 Zhi Wang [this message]
2015-07-21 12:46 ` About the wait_for() macro in intel_drv.h Wang, Zhi A

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