From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 4BFD6DDE35 for ; Tue, 2 Oct 2007 16:24:23 +1000 (EST) Subject: Re: [PATCH 3/4] Simplify rtas_change_msi() error semantics From: Benjamin Herrenschmidt To: michael@ellerman.id.au In-Reply-To: <1191304690.6593.8.camel@concordia> References: <3034ec8fd939bd5cfcdb7ac65206ae2771dc9b2c.1190270165.git.michael@ellerman.id.au> <1191302603.6310.88.camel@pasglop> <1191304690.6593.8.camel@concordia> Content-Type: text/plain Date: Tue, 02 Oct 2007 16:24:13 +1000 Message-Id: <1191306253.6310.106.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2007-10-02 at 15:58 +1000, Michael Ellerman wrote: > > Looks allright, just a question tho... what do we do if it fails ? > Do we > > try to fallback to a lower number of MSIs ? Or what ? Dead device ? > > That's all up to the device driver. In theory the driver could try again > with a lower count - but that might require extra logic in the driver to > handle shared irq handlers etc. In practice I think the current drivers > will just fail. Question is badly phrased.. I meant something more like... what do we do if RTAS returns a lower count ? That is, we end up with that device with that lower count of MSIs enabled, we fail at the driver level, do we still somewhat keep track ? Drivers might assume that means it can use LSIs no ? which may not be the case... Shouldn't we try to switch back to LSI mode (or does the RTAS interface doesnt allow it ?) Ben.