On Thu, Apr 23, 2015 at 5:30 PM, Bjorn Helgaas bhelgaas@google.com wrote:
[+cc Matthew]
On Tue, Apr 21, 2015 at 09:07:45AM -0700, Linus Torvalds wrote:
Hmm. The odd Intel PCI resource mess is back.
Or maybe it never went away.
I get these when suspending. Things *work*, but it's really spamming my logs a fair bit:
i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment pci_bus 0000:01: Allocating resources pci_bus 0000:02: Allocating resources i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment
That resource is complete garbage. "flags 0x2" is not even a valid flag value. I'm *guessing* it might be IORESOURCE_ROM_SHADOW, but if that is valid, then it should also have have had the IORESOURCE_MEM bit, and it doesn't.
Your i915 does not have a ROM BAR in hardware. If the default video device has no ROM BAR, pci_fixup_video() sets IORESOURCE_ROM_SHADOW even though the resource flags are zero because the BAR itself doesn't exist.
If IORESOURCE_ROM_SHADOW is set, pci_map_rom() assumes there's a shadow ROM image at 0xC0000. Is there a shadow image even if the device itself doesn't have a ROM BAR?
Very likely yes. With integrated APUs and mobile dGPUs, the vbios image is often stored as part of the system rom rather than as a dedicated rom for the GPU. The vbios image is then copied to the shadow location during sbios init to provide OS access to the rom.
Alex
We could fabricate a resource even if the BAR doesn't exist, e.g., "flags = IORESOURCE_MEM | ... | IORESOURCE_ROM_SHADOW", but that would be ugly and error-prone in other places that use the ROM.
Matthew added dev->rom for ROM images supplied by the platform (84c1b80e3263 ("PCI: Add support for non-BAR ROMs")). A shadow image seems like a similar thing. I think it would be cleaner to get rid of IORESOURCE_ROM_SHADOW altogether and instead set "dev->rom = 0xC0000" if there's a shadow image, e.g.:
int pcibios_add_device(struct pci_dev *dev) { if (dev-is-default-vga-device) { dev->rom = 0xC0000; dev->romlen = 0x20000; }
pa_data = boot_params.hdr.setup_data; while (pa_data) { ... if (data->type == SETUP_PCI) { rom = (struct pci_setup_rom *)data; if (dev-is-rom-dev) { dev->rom = ... dev->romlen = rom->pcilen; } } }But the rules for figuring out which image to use seem ... complicated.
Bjorn _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel