From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Fri, 26 Jun 2015 22:43:32 +0200 Subject: [PATCH 1/1] pci: xgene: Enable huge outbound bar support In-Reply-To: <46305464.n5SOjGAhJb@wuerfel> References: <1435280756-24455-1-git-send-email-dhdang@apm.com> <46305464.n5SOjGAhJb@wuerfel> Message-ID: <1674778.6xGik39Z0J@wuerfel> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 26 June 2015 22:35:08 Arnd Bergmann wrote: > > > > > > Can you configure one of the two windows as prefetchable for improved performance? > > > > > The new huge window will be prefetchable. > > The DT marks it as non-prefetchable, so the kernel will now try to allocate > space for non-prefetchable BARs from this area, which is a bug. If the second > memory window is always prefetchable, you have to mark it accordingly in DT, > to prevent it from being used for normal 64 bit BARs. Forget what I wrote here, I just remembered that 64-bit BARs are by definition prefetchable. You should still mark the range accordingly in DT for correct operation, but it won't be used for non-prefetchable 64-bit BARs if you don't because they do not exist. Arnd