Re: [PATCH] PCI: Only enable IO window if supported

From: Guenter Roeck
Date: Tue Jul 07 2015 - 11:02:04 EST


Hi Lorenzo,

On 07/07/2015 07:40 AM, Lorenzo Pieralisi wrote:
On Fri, Jun 19, 2015 at 05:24:13PM +0100, Lorenzo Pieralisi wrote:
Hi Guenter,

On Thu, Jun 18, 2015 at 07:01:03PM +0100, Guenter Roeck wrote:
On Thu, May 28, 2015 at 07:41:12AM -0500, Bjorn Helgaas wrote:

I'd like res->flags to reflect the capabilities of the hardware, not
whether the window is currently enabled.

Flag bits seem to be all taken. Could we use IORESOURCE_DISABLED for that
purpose, or could that cause conflicts elsewhere ?

Yes, I think IORESOURCE_DISABLED would be appropriate for any I/O windows
below a host bridge that doesn't support I/O space.

I integrated Lorenzo's patch and tried to get this working.

Thanks. How do you want to proceed with this ? Are you taking my patch
and post it along with your updated series ? We need to extend test
coverage to platforms we could not test on, as you know my series
affects all archs but SPARC (I mean it should *not* affect them, this
has to be tested though, I do not have the HW needed, your coverage
for x86 and PowerPC is great but I do not think it can be deemed
sufficient).

Please let me know, thanks !

Any comment on this ? I will have to remove the bridge resource claiming
from my patch according to Ben's concerns for PowerPC, which requires
a v3.

How do you want me to go on with this ?


Can you send your v3 ?

I didn't submit my latest version because I recalled Ben's objections,
and I never got around asking you if you plan to send a new version
of your patch.

I had to drop the idea of using IORESOURCE_DISABLED; pretty much all
kernel code uses the "!flags" test to identify unused resources.
I tried to change that, but just could not get it to work.
I ended up introducing a new bus flag instead, PCI_BUS_FLAGS_NO_IO,
which works quite nicely since it propagates to child buses.

Thanks,
Guenter

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/