From: swarren@wwwdotorg.org (Stephen Warren)
Date: Wed, 15 Aug 2012 13:04:20 -0600
Subject: [PATCH v3 00/10] ARM: tegra: Add PCIe device tree support
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To: linux-arm-kernel@lists.infradead.org
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On 08/14/2012 05:51 PM, Stephen Warren wrote:
> On 08/14/2012 04:58 PM, Stephen Warren wrote:
...
>> Can't we make the call to pci_bus_add_devices() optional in
>> pci_scan_root_bus() somehow; one of:
> 
> Sigh, that turns out not to work correctly; it solves at least this part
> of the problem when booting using device tree, but when booting using a
> board file, it causes the IRQ number passed to the PCIe device to be
> bogus:-(
> 
> I give up for now.

I think the appropriate workaround for Tegra in 3.6 is to simply make
any drivers for PCIe-based devices be modules instead of built-in, as
Thierry hinted at much earlier in the thread. I've validated that the
Ethernet works just fine on TrimSlice with that change, booting v3.6-rc1
using either board files or device tree.

For 3.7, we should continue the discussion about a real fix; I'll look
into the change Bjorn requested and see if it works, although given that
hacking pci_scan_root_bus as described immediately previously in this
thread caused a regression when booting using a board file, and the fact
that board files are no longer supported on Tegra, I'm not too confident
in the outcome...