Messages in this thread | | | Date | Wed, 9 Apr 2014 09:56:24 +0200 | From | Willy Tarreau <> | Subject | Re: [PATCH v2] bus: mvebu-mbus: Avoid setting an undefined window size |
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On Wed, Apr 09, 2014 at 09:53:50AM +0200, Thomas Petazzoni wrote: > Dear Willy Tarreau, > > On Wed, 9 Apr 2014 09:47:52 +0200, Willy Tarreau wrote: > > > > Yes, the panic is expected: Jason's patch is not *fixing* anything, > > > it's just telling you *why* it's going to panic. > > > > I just thought that the EINVAL would prevent one from registering > > the device, which would be more useful (if at all possible). > > Unfortunately, I don't think that's possible: the function that sets up > the MBus window is called by the emulated bridge code, i.e when the > Linux PCI core thinks it is doing a write to a bridge register. And I > don't think there is a way of "refusing" the write to let the Linux > PCI core know that it was not possible to set up the bridge BAR as it > was requested. > > Maybe this is something that Jason can confirm/infirm. I remember > having a quick look at the core Linux PCI core to see if it was > somehow checking whether the bridge BAR has been properly configured, > but I think I concluded it was not the case, and it was just assuming > that write the memory base/limit in the bridge registers was > sufficient.
OK thanks for the detailed explanation!
Willy
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