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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