On Sep 12, 2007, at 9:45 AM, Josh Boyer wrote: > On Thu, 30 Aug 2007 10:33:28 +0200 > Stefan Roese <[EMAIL PROTECTED]> wrote: > >> Problem Description and Fix : Memory Read Multiples(MRM) do not work >> correctly on PPC 440EPX based systems. A PCI driver determines >> whether >> MRMs are supported by reading the PCI cache line size register. If >> this >> value is zero then MRMs are not supported. However some PCI drivers >> write to the PCI cache line size register on initialization. This >> results in MRMs being sent to system memory on 440EPX based systems. >> Since MRMs do not work correctly in 440EPX based systems this may >> cause >> system hang. This patch solves this problem by modifying the PPC >> platform specific PCI configuration register write function, by >> forcing >> any value written to PCI_CACHE_LINE_SIZE register to be 0. This >> fix was >> tested on different PCI cards : i.e. Silicon Image ATA card and Intel >> E1000 GIGE card. On Silicon Image ATA card without this fix in place >> creating a filesystem on IDE drive "mke2fs /dev/hda" was hanging the >> system. MRMs issued by the PCI card were seen on the PCI analyzer >> since >> the Silicon Image driver was setting the PCI_CACHE_LINE_SIZE >> register to >> 255. With this patch the PCI_CACHE_LINE_SIZE register was 0 and only >> Memory Reads were seen on PCI analyzer. >> >> Signed-off-by: Pravin M. Bathija <[EMAIL PROTECTED]> >> Signed-off-by: Stefan Roese <[EMAIL PROTECTED]> >> >> --- >> I know this patch is a little "dirty", but perhaps somebody has a >> better >> idea to fix this problem. Thanks. > > For the peanut gallery, Stefan and I discussed this a bit on IRC today > and a different approach for arch/powerpc is going to be looked at > instead. Namely, introducing a new flag for indirect_type in the > pci_controller structure to key off of instead of having ifdefs.
I assume you'll be adding to the 'quirk' flags that we already have in place. - k _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
