netdev - Re: sblk->status_tag on drivers/net/ethernet/broadcom/tg3.c

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Date:	Wed, 5 Mar 2014 09:33:52 +0530
From:	Jagan Teki <jagannadh.teki@...il.com>
To:	Michael Chan <mchan@...adcom.com>
Cc:	netdev@...r.kernel.org,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	Nithin Nayak Sujir <nsujir@...adcom.com>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: sblk->status_tag on drivers/net/ethernet/broadcom/tg3.c

On Wed, Mar 5, 2014 at 4:52 AM, Michael Chan <mchan@...adcom.com> wrote:
> On Tue, 2014-03-04 at 23:25 +0530, Jagan Teki wrote:
>> From the comments in ISR any non-zero value to intr-mbox-0 clear
>> the interrupt ie write status as 1 so I assume interrupt is clear and then
>> in tg3_int_reenable is going to write 0x0 on to intr-mbox-0
>> which again reenables the interrupt, was my guess is true?
>
> Yes, the (last_tag << 24) is also written to the intr-mbox-0 to
> acknowledge the status block.

Yes, I saw it.

>
>> And sblk->status_tag is always 0 in ISR and BH(poll) why is that so?
>> If it's is 1(unsigned non-zero) then possibly tg3_int_reenable will write
>> non-zero value on intr-mbox-0 which will clear the interrupt.
>
> You should print out the entire status block.  It shouldn't be zero.
> The status tag should be incrementing for each interrupt.

I see the status_tag is 0, at starting of ISR.
OK will try to print entire block members.

>> Request for any help who updates sblk->status_tag value and
>> how many time the ISR in PCIe RC and ISR in EP will call for link up?
>>
>>
> If you are expecting link up, the first 32-bit word of the status block
> should have bit 1 set (bit 0 should also be set).  I think the driver is
> not seeing the status block correctly, so it is not acknowledging the
> link change interrupt and the status_tag.

The driver is not seeing the status block mean - tg3.c driver?
Does it relates to ISR or addressing of PCIe RC driver, I'm doing
nothing on my PCIe RC driver just read the legacy INT# status and return.

Any inputs if you see it on PCIe RC, let me know.

thanks!
-- 
Jagan.
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