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From: Mark Lord <mlord@pobox.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Yinghai Lu <yinghai@kernel.org>, "Theodore Ts'o" <tytso@mit.edu>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: driver skip pci_set_master, fix it? No.
Date: Wed, 09 Apr 2014 09:08:48 -0400	[thread overview]
Message-ID: <53454660.5090603@pobox.com> (raw)
In-Reply-To: <1397011868.3671.94.camel@pasglop>

On 14-04-08 10:51 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2014-04-08 at 17:18 -0400, Mark Lord wrote:
>>> I assume you're talking about the one added by cf3e1feba7f9 ("PCI:
>>> Workaround missing pci_set_master in pci drivers"), but as far as I
>>> can tell, it only calls pci_set_master() for *bridge* devices.  What
>>> am I missing?  Is pci_set_master() being called for your endpoint?
>>> What path is that?
>>
>> Yes, it is being called during execution of the _probe() function in my driver,
>> as evidenced by the annoying (and wrong) message it produces.
>>
>> Next time I've got the hardware at hand, I'll put a "dump_stack()" into there
>> to see the exact calling path.
> 
> Note that one of the reason we want to do it early on bridges is that without it,
> we may also not get the PCIe error messages.

Sure, for bridges.

I'll get a stack trace later today, but what I suspect is happening
is that this multi-function card is being treated by the PCI layers
as a "bridge" for purposes of the multiple virtual functions it implements.

We will probably need to distinguish this kind of device from real bridges here.
-- 
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com

  reply	other threads:[~2014-04-09 13:08 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-08 16:34 driver skip pci_set_master, fix it? No Mark Lord
2014-04-08 18:27 ` Bjorn Helgaas
2014-04-08 21:18   ` Mark Lord
2014-04-09  2:51     ` Benjamin Herrenschmidt
2014-04-09 13:08       ` Mark Lord [this message]
2014-04-09 14:12         ` Mark Lord
2014-04-09 14:18           ` Mark Lord
2014-04-09 15:52             ` Bjorn Helgaas
2014-04-09 16:40               ` Mark Lord
2014-04-09 17:26                 ` Bjorn Helgaas

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