From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: Re: [RFC PATCH] vfio: add fixup for broken PCI devices Date: Fri, 25 May 2012 06:24:10 -0600 Message-ID: <1337948650.4714.88.camel@ul30vt> References: <4FBF3627.3030504@ozlabs.ru> <1337934518.16119.15.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Alexey Kardashevskiy , qemu-devel@nongnu.org, Alex Graf , kvm@vger.kernel.org, David Gibson To: Benjamin Herrenschmidt Return-path: In-Reply-To: <1337934518.16119.15.camel@pasglop> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org On Fri, 2012-05-25 at 18:28 +1000, Benjamin Herrenschmidt wrote: > On Fri, 2012-05-25 at 17:35 +1000, Alexey Kardashevskiy wrote: > > Some adapters (like NEC PCI USB controller) do not flush their config > > on a sioftware reset and remember DMA config, etc. > > > > If we use such an adapter with QEMU, then crash QEMU (stop it with > > ctrl-A ctrl-X), and try to use it in QEMU again, it may start working > > immediately with previous config when pci_enable_device() is called > > on that PCI function. > > > > To eliminate such effect, some quirk should be called. The proposed > > pci_fixup_final does its job well for mentioned NEC PCI USB but not > > sure if it is 100% correct. > > I think we should create a new quirk category... call it pci_fixup_reset > or something like that, which is responsible for blasting the thing into > submission when ownership changes. > > We'll need these for more than just USB I suspect. We already have pci_dev_specific_reset() called from pci_dev_reset(). Does this device support any of the standard reset mechanisms? It would be nice to know what within the final fixups keeps this device working. Thanks, Alex