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Subject: Re: Is it useful to support user level drivers
To: D.A.Fedorov@inp.nsk.su
Date: Thu, 21 Jun 2001 14:28:10 +0100 (BST)
Cc: alan@lxorguk.ukuu.org.uk (Alan Cox), balbir_soni@yahoo.com (Balbir Singh),
        linux-kernel@vger.kernel.org
In-Reply-To: <Pine.SGI.4.10.10106211905030.3193032-100000@Sky.inp.nsk.su> from "Dmitry A. Fedorov" at Jun 21, 2001 07:45:51 PM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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> Lastly an IRQ kernel module can disable_irq() from interrupt handler
> and enable it again only on explicit acknowledge from user.

No. The IRQ might be shared, and you get a slight problem if you just disabled
an IRQ needed to make progress for user space to handle the IRQ