From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: AHCI question Date: Mon, 22 Nov 2010 11:42:52 -0500 Message-ID: <20101122164252.GC21254@dumpdata.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Kamala Narasimhan Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Mon, Nov 22, 2010 at 09:51:26AM -0500, Kamala Narasimhan wrote: > I am writing a polled mode Xen AHCI driver to collect some minimal What is a 'Xen AHCI' driver? > information after a system crash. As dom0 would have initialized and > used the HBA before we enter the crashing code path, I am not doing > any kind of device initialization within the Xen AHCI driver. I am > also not setting up interrupts etc. as the driver is used in polled > mode. I simply map the abar and other memory regions associated with > the device that dom0 has already setup and write to it/read from it as > needed. > > After a crash, within the Xen AHCI driver I am able to get to the pci > space for the device, get valid HBA registers, mapping etc. works but > the HBA does not respond back after I issue a command for execution. > In specific, after I set the port x command issue register (pxci) for > the free slot, that slot is not getting cleared as it should after a > command execution. > > As an experiment to see if anything at all works with respect to > setting/resetting port registers, I simply decided to stop/start the > HBA command engine by setting the ST bit in the command register > (PxCMD) to 0 and then checking if CR, FR bit etc. in PxCMD are reset > by HBA after a ST reset but they remain set. > > I am hoping someone with AHCI experience might be able to shed some > light as to why the HBA is not responding as it should. Thanks. > > Kamala > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel