From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=37174 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OGnIQ-0003Ya-Et for qemu-devel@nongnu.org; Tue, 25 May 2010 02:07:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OGnIO-0006nY-PJ for qemu-devel@nongnu.org; Tue, 25 May 2010 02:07:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60081) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OGnIO-0006nP-Ga for qemu-devel@nongnu.org; Tue, 25 May 2010 02:07:20 -0400 Date: Tue, 25 May 2010 09:07:15 +0300 From: Gleb Natapov Subject: Re: [Qemu-devel] [RFT][PATCH 07/15] qemu_irq: Add IRQ handlers with delivery feedback Message-ID: <20100525060715.GN22163@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: blue Swirl , Jan Kiszka , qemu-devel@nongnu.org, Juan Quintela On Mon, May 24, 2010 at 10:13:40PM +0200, Jan Kiszka wrote: > From: Jan Kiszka > > This allows to communicate potential IRQ coalescing during delivery from > the sink back to the source. Targets that support IRQ coalescing > workarounds need to register handlers that return the appropriate > QEMU_IRQ_* code, and they have to propergate the code across all IRQ > redirections. If the IRQ source receives a QEMU_IRQ_COALESCED, it can > apply its workaround. If multiple sinks exist, the source may only > consider an IRQ coalesced if all other sinks either report > QEMU_IRQ_COALESCED as well or QEMU_IRQ_MASKED. > Well, almost two years passed since this approach was proposed first time[1] ;). Back then it generated bunch of nonsensical comments about real hardware not working this way, so the hack that we have now was introduce to overcome this resistance. I hope enough time passed for people to gain some sense and the approach will be adopted this time. Really this should have been done two year ago. [1] http://lists.nongnu.org/archive/html/qemu-devel/2008-06/msg00757.html -- Gleb.