On Wed, Jul 05, 2017 at 10:39:19PM +0200, Mason wrote:

On 05/07/2017 20:03, Bjorn Helgaas wrote:

quoted

On Wed, Jul 05, 2017 at 12:55:37AM +0200, Mason wrote:

quoted

On 04/07/2017 22:24, Bjorn Helgaas wrote:

quoted

I made the trivial changes I mentioned, added a dependency on
CONFIG_BROKEN (for the config/MMIO muxing issue), and put these on
pci/host-tango.  I can't build or test this, so I probably broke
something in the process.  I think the combination of the boot-time
warning, the taint, and CONFIG_BROKEN is a reasonable amount of
warning that a user should expect issues.

Can you take a look and see if it works for you?

https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?h=pci/host-tango

Thanks. I'll take it for a spin ASAP.

TAINT_CRAP... Smirk. I didn't see that one in the docs:
https://www.kernel.org/doc/html/latest/admin-guide/tainted-kernels.html

Oh wait... TAINT_CRAP is "C" => a staging driver has been loaded

I wish it had a less pejorative, more descriptive name.  But it seems like
the closest to this situation.

Maybe it is not too late to submit a patch to Linus
renaming TAINT_CRAP?

Here are a few candidates, off the top of my head:

TAINT_STAGING
TAINT_STAGING_DRIVER
TAINT_BROKEN_HW
TAINT_BROKEN_HARDWARE
TAINT_USE_AT_YOUR_OWN_RISK

I personally wouldn't object, but it's not a PCI thing so that can all
be separate from this driver.

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The one issue I anticipate with "depends on BROKEN" is
when I add support for revision 2, which isn't broken.

How about this:

  - Rename PCIE_TANGO to PCIE_TANGO_REV1
  - PCIE_TANGO_REV1 depends on BROKEN
  - Add rev2 support later, enabled by PCIE_TANGO
  - PCIE_TANGO_REV1 depends on PCIE_TANGO && BROKEN

I updated pci/host-tango along these lines (without rev2 support,
obviously).

And support for REV1 wouldn't be compiled in, unless
BROKEN is selected? Yes, I think that could fly.

Right.

Don't you think the naming should follow the DT
convention of using the first SoC embedding the
IP (for the compatible string) ?

PCIE_TANGO_REV1 vs PCIE_TANGO_SMP8759

Sounds reasonable.  So v2 will be something other than SMP8759?
I renamed it to CONFIG_PCIE_TANGO_SMP8759.

quoted

I forgot to ask for a MAINTAINERS update.  Can you send that, too,
please?

There's a "catch-all" rule for everything tango-related:

ARM/TANGO ARCHITECTURE
M:	Marc Gonzalez [off-list ref]
L:	linux-arm-kernel at lists.infradead.org
S:	Maintained
N:	tango

Is that enough?

Yep, sorry I didn't notice that.  That's enough for
scripts/get_maintainer.pl to work, which is what I'm looking for.

If you confirm that
https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/commit/?h=pci/host-tango&id=d752a8b29345
works for you, I'll include it in my v4.13 pull request.

Bjorn