Messages in this thread | | | Date | Mon, 1 Aug 2005 19:35:17 -0400 | From | Dave Jones <> | Subject | pci cacheline size / latency oddness. |
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During boot of todays -git, I noticed this..
PCI: Setting latency timer of device 0000:00:1d.7 to 64
after boot, lspci shows..
00:1d.7 USB Controller: Intel Corporation 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller (rev 02) (prog-if 20 [EHCI]) Subsystem: Dell: Unknown device 0169 Flags: bus master, medium devsel, latency 0, IRQ 201 ^^
It also complains about..
PCI: cache line size of 128 is not supported by device 0000:00:1d.7
x86-64 doesn't have an arch override for pci_cache_line_size, so it ends up at L1_CACHE_BYTES >> 2, which is 128 if you build x86-64 kernels with CONFIG_GENERIC_CPU or CONFIG_MPSC This means we will do the wrong thing on AMD machines which have 64 byte cachelines. I saw this problem however on an em64t box. Would it make sense to shift >> once more if it fails, and retry with a smaller size perhaps ?
Dave
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