From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: [parisc-linux] Re: [PATCH] PCMCIA: Disable probing on parisc Date: Tue, 6 Dec 2005 09:36:44 +0000 Message-ID: <20051206093643.GA1706@flint.arm.linux.org.uk> References: <20051204060423.GA12355@quicksilver.road.mcmartin.ca> <20051204103338.GA16791@flint.arm.linux.org.uk> <1133818340.3395.11.camel@mulgrave> <20051205220344.GJ15201@flint.arm.linux.org.uk> <1133829923.3262.1.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-pcmcia@lists.infradead.org, parisc-linux@lists.parisc-linux.org, Kyle McMartin To: James Bottomley Return-Path: In-Reply-To: <1133829923.3262.1.camel@mulgrave> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org On Mon, Dec 05, 2005 at 07:45:23PM -0500, James Bottomley wrote: > On Mon, 2005-12-05 at 22:03 +0000, Russell King wrote: > > The probing code sets up a mapping to place the CIS at one of the > > regions, and then tries to validate/read the CIS. It then unmaps > > it and maps it into the next place and repeats. Hence, we're > > reading data from the PCMCIA card after setting up various valid > > mappings. > > Yes, that's what crashes. Any memory probe to a non-responding address > on PA causes a high priority machine check. This is what trips us up. > We have to explicitly list the responding regions in the config file. I don't think you've fully understood what I've been saying. When we try to do memory probing, we setup a mapping in the same way that we setup a mapping to read the CIS from the card. Therefore, when we read from the regions we're probing, we should see valid CIS data. Therefore, we are _not_ accessing an address which doesn't respond, but we're accessing an address which we've asked the PCMCIA bridge to map the card memory to. If the hardware decides that, despite us setting up such a mapping, the address we're accessing is not valid, then rather than disabling the probing we should not ask PCMCIA to use it because the address range is not available. In either case, if the memory probe fails in some way, the solution is not to disable it because then you're just papering over whatever real problem exists. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux