Messages in this thread | | | Date | Wed, 6 Aug 2014 12:56:04 -0400 | From | Murali Karicheri <> | Subject | Re: [PATCH] PCI: keystone: add a pci quirk to limit mrrs |
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On 08/06/2014 12:30 PM, Jason Gunthorpe wrote: > On Wed, Aug 06, 2014 at 11:18:20AM -0400, Murali Karicheri wrote: >> Keystone PCI controller has a limitation that memory read request >> size must not exceed 256 bytes. This is a hardware limitation and >> add a quirk to force this limit on all downstream devices by >> updating mrrs. > > Does this still work if the tuning is enabled, or does the tuning run > after this?
Yes it works with tuning enabled. Tuning happens afterwards. The 'limiting mrrs to 256' below is from my patch.
[ 2.267670] limiting mrrs to 256 [ 2.267698] limiting mrrs to 256 [ 2.267808] pcieport 0000:00:00.0: BAR 8: assigned [mem 0x50000000-0x500fffff] [ 2.267818] pcieport 0000:00:00.0: BAR 9: assigned [mem 0x50100000-0x501fffff pref] [ 2.267827] pcieport 0000:00:00.0: BAR 7: assigned [io 0x1000-0x1fff] [ 2.267840] pci 0000:01:00.0: BAR 0: assigned [mem 0x50000000-0x5001ffff] [ 2.267855] pci 0000:01:00.0: BAR 1: assigned [mem 0x50020000-0x5003ffff] [ 2.267869] pci 0000:01:00.0: BAR 6: assigned [mem 0x50100000-0x5011ffff pref] [ 2.267877] pci 0000:01:00.1: BAR 0: assigned [mem 0x50040000-0x5005ffff] [ 2.267891] pci 0000:01:00.1: BAR 1: assigned [mem 0x50060000-0x5007ffff] [ 2.267904] pci 0000:01:00.1: BAR 6: assigned [mem 0x50120000-0x5013ffff pref] [ 2.267913] pci 0000:01:00.0: BAR 2: assigned [io 0x1000-0x101f] [ 2.267926] pci 0000:01:00.1: BAR 2: assigned [io 0x1020-0x103f] [ 2.267946] pcieport 0000:00:00.0: Max Payload Size set to 256/ 256 (was 128), Max Read Rq 256 [ 2.267980] pci 0000:01:00.0: Max Payload Size set to 256/ 256 (was 128), Max Read Rq 256 [ 2.268013] pci 0000:01:00.1: Max Payload Size set to 256/ 256 (was 128), Max Read Rq 256
> >> + if (pcie_get_readrq(dev)> 256) { >> + pr_info("limiting mrrs to 256\n"); >> + pcie_set_readrq(dev, 256); > > The pr_info should either go away, or at least print the PCI bdf..
I will change this to a dev_info and print the PCI bdf as part of it.
> > Jason
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