Re: Out-of-tree mwlwifi driver crashes

[Leigh Brown <leigh@solinno.co.uk>]

Hi Thomas,

On 2019-01-31 15:46, Thomas Petazzoni wrote:
> Hello Leigh,
> 
> On Tue, 29 Jan 2019 15:36:56 +0000
> Leigh Brown <leigh@solinno.co.uk> wrote:
> 
>> Apologies, I use webmail.  I have attached two files with the results
>> from running lspci -vvv -xxx
> 
> Thanks, that was very useful. I believe the issue comes from the fact
> that your PCIe device has prefetchable BARs, while none of the 5 PCIe
> devices I have here has prefetchable BARs. The pci-mvebu driver doesn't
> support such BARs, but the change to the common PCI bridge emulation
> logic made the prefetchable memory base / limit register read-write
> while they were read-only before.
> 
> To verify this hypothesis, could you apply the following patch (on top
> of 4.20), and see if it solves the problem ? Thanks!
> 
> This is probably not the right/correct fix, but it will at least allow
> to verify that the problem is understood correctly.
> 
> Thomas
> 
> diff --git a/drivers/pci/pci-bridge-emul.c 
> b/drivers/pci/pci-bridge-emul.c
> index 129738362d90..f99b80c19809 100644
> --- a/drivers/pci/pci-bridge-emul.c
> +++ b/drivers/pci/pci-bridge-emul.c
> @@ -142,11 +142,7 @@ const static struct pci_bridge_reg_behavior
> pci_regs_behavior[] = {
>         },
> 
>         [PCI_PREF_MEMORY_BASE / 4] = {
> -               /* The high 12-bits of pref mem base/limit are RW */
> -               .rw = GENMASK(31, 20) | GENMASK(15, 4),
> -
> -               /* The low four bits of pref mem base/limit are RO */
> -               .ro = GENMASK(19, 16) | GENMASK(3, 0),
> +               .ro = ~0,
>         },
> 
>         [PCI_PREF_BASE_UPPER32 / 4] = {

Thanks for responding. I had to manually apply the patch, but it 
certainly fixes
the issue.

Regards,

Leigh.