linux-kernel - Re: [Intel-gfx] agp/intel: can't ioremap flush page

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Date:	Tue, 11 Mar 2014 00:45:21 +0100
From:	Paul Bolle <pebolle@...cali.nl>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	Steven Newbury <steve@...wbury.org.uk>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	David Airlie <airlied@...ux.ie>,
	intel-gfx <intel-gfx@...ts.freedesktop.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Yinghai Lu <yinghai@...nel.org>, linux-pci@...r.kernel.org
Subject: Re: [Intel-gfx] agp/intel: can't ioremap flush page - no chipset
 flushing

Bjorn Helgaas schreef op ma 10-03-2014 om 12:24 [-0600]:
> Thanks.  Can you try the patch below?  I think it should fix the problem.
> 
> 
> PCI: Don't check resource_size() in pci_bus_alloc_resource()
> 
> From: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> When resource_size_t is 32 bits wide, e.g., when CONFIG_PHYS_ADDR_T_64BIT
> is not defined, resource_size() on [mem 0x00000000-0xffffffff] returns 0
> because (r->end - r->start + 1) overflows.
> 
> Therefore, we can't use "resource_size() == 0" to decide that allocation
> from this resource will fail.  allocate_resource() should fail anyway if it
> can't satisfy the address constraints, so we should just depend on that.
> 
> A [mem 0x00000000-0xffffffff] bus resource is obviously not really valid,
> but we do fall back to it as a default when we don't have information about
> host bridge apertures.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=71611
> Fixes: f75b99d5a77d PCI: Enforce bus address limits in resource allocation
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> ---
>  drivers/pci/bus.c |    2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> index 00660cc502c5..38901665c770 100644
> --- a/drivers/pci/bus.c
> +++ b/drivers/pci/bus.c
> @@ -162,8 +162,6 @@ static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res,
>  
>  		avail = *r;
>  		pci_clip_resource_to_region(bus, &avail, region);
> -		if (!resource_size(&avail))
> -			continue;
>  
>  		/*
>  		 * "min" is typically PCIBIOS_MIN_IO or PCIBIOS_MIN_MEM to

I've applied your patch on top of v3.14-rc6. The boot warning is gone.
And /proc/iomem once again has the lines:
    [...]
    80000000-801fffff : PCI Bus 0000:02
    80200000-8027ffff : 0000:00:02.1
    80280000-80280fff : Intel Flush Page
    [...]

Which is what we want, don't we?

A bit of doubt is caused by two new boot time messages:
    pnp 00:00: unknown resource type 10 in _CRS
    pnp 00:00: can't evaluate _CRS: 1

But I haven't yet tried v3.14-rc6 without your patch, so these might be
unrelated. They're unclear to me, anyway.

Thanks,


Paul Bolle

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