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From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: Nicolas Chauvet <kwizart@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	<linux-tegra@vger.kernel.org>, <linux-pci@vger.kernel.org>
Subject: Re: [RFC] PCI: tegra: Revert raw_violation_fixup for tegra124
Date: Fri, 26 Jun 2020 20:00:13 +0530	[thread overview]
Message-ID: <4acabca8-e2fc-b660-0c37-c5f332b99084@nvidia.com> (raw)
In-Reply-To: <CABr+WT=Gy6vmB-GdCeR_q8ogB4b19LDqQV5mjNh5VvZ0BUJKig@mail.gmail.com>


On 26-Jun-20 6:52 PM, Nicolas Chauvet wrote:
> External email: Use caution opening links or attachments
>
>
> Le lun. 20 avr. 2020 à 20:16, Manikanta Maddireddy
> <mmaddireddy@nvidia.com> a écrit :
>> Thank you Nicolas for identifying the patch which caused the CmpltTO.
>>
>> Little background on the fixup,
>>  In the internal testing with dGPU on Tegra124, CmplTO is reported by
>> dGPU. This happened because FIFO queue in AFI(AXI to PCIe) module
>> get full by upstream posted writes. Back to back upstream writes
>> interleaved with infrequent reads, triggers RAW violation and CmpltTO.
>> This is fixed by reducing the posted write credits and by changing
>> updateFC timer frequency. These settings are fixed after stress test.
>>
>> In the current case, RTL NIC is also reporting CmplTO. These settings
>> seems to be aggravating the issue instead of fixing it.
> Seems I've lost track of this  issue.
>
> @Manikanta Maddireddy  Do you plan to have some time to work on this ?

Unfortunately, I don't have access to T124 platform because of lock down.

> If going with the revert I wonder if I need to revert more completely
> the original patch ? Since only tegra124 used the raw_violation_fixup,
> should I remove this case and the related function completely or leave
> the code as is ? (there will be few unused functions maybe). Given
> other fixup have been added at a later time, the full revert is less
> trivial.

There are no unused functions, small piece of code under raw_violation_fixup
check will become redundant. Yes, revert will give conflicts.
I may not get a chance to work on this bug in coming months. If possible,
please do complete revert. Once I get a chance to work on this bug, I will
send out new patch.

-Manikanta

>
> Right now this partial revert is enough to work reliably with the device.
>
> Thanks for your advice.
> I will send a non-RFC version then.


      reply	other threads:[~2020-06-26 14:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 16:43 [RFC] PCI: tegra: Revert raw_violation_fixup for tegra124 Nicolas Chauvet
2020-04-20 18:15 ` Manikanta Maddireddy
2020-06-26 13:22   ` Nicolas Chauvet
2020-06-26 14:30     ` Manikanta Maddireddy [this message]

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