Re: [PATCH] PCI: quirks: Quirk PCI d3hot delay for AMD xhci

From: "Limonciello, Mario" <mario.limonciello@amd.com>
To: Bjorn Helgaas <helgaas@kernel.org>,
	Alex Deucher <alexander.deucher@amd.com>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org,
	Marcin Bachry <hegel666@gmail.com>,
	prike.liang@amd.com, shyam-sundar.s-k@amd.com
Subject: Re: [PATCH] PCI: quirks: Quirk PCI d3hot delay for AMD xhci
Date: Thu, 29 Jul 2021 15:42:58 -0500	[thread overview]
Message-ID: <7b6c6fad-8cda-537a-2178-f5e22e565e8c@amd.com> (raw)
In-Reply-To: <20210729203914.GA987812@bjorn-Precision-5520>

On 7/29/2021 15:39, Bjorn Helgaas wrote:
> On Wed, Jul 21, 2021 at 10:58:58PM -0400, Alex Deucher wrote:
>> From: Marcin Bachry <hegel666@gmail.com>
>>
>> Renoir needs a similar delay.
>>
>> [Alex: I talked to the AMD USB hardware team and the
>>   AMD windows team and they are not aware of any HW
>>   errata or specific issues.  The HW works fine in
>>   windows.  I was told windows uses a rather generous
>>   default delay of 100ms for PCI state transitions.]
>>
>> Signed-off-by: Marcin Bachry <hegel666@gmail.com>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> 
> Added stable tag and applied to pci/pm for v5.15, thanks!

Thanks Bjorn!

Given how small/harmless this is and 5.14 isn't cut yet, any chance this 
could still make one of the -rcX rather than wait for 5.14.1 instead?

> 
>> Cc: mario.limonciello@amd.com
>> Cc: prike.liang@amd.com
>> Cc: shyam-sundar.s-k@amd.com
>> ---
>>
>> Bjorn,
>>
>> With the above comment in mind, would you consider this patch
>> or would you prefer to increase the default timeout on Linux?
>> 100ms seems a bit long and most devices seems to work within
>> that limit.  Additionally, this patch doesn't seem to be
>> required on all AMD platforms with the affected USB controller,
>> so I suspect the current timeout on Linux is probably about
>> right.  Increasing it seems to fix some of the marginal cases.
>>
>> Alex
>>
>>   drivers/pci/quirks.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
>> index 22b2bb1109c9..dea10d62d5b9 100644
>> --- a/drivers/pci/quirks.c
>> +++ b/drivers/pci/quirks.c
>> @@ -1899,6 +1899,7 @@ static void quirk_ryzen_xhci_d3hot(struct pci_dev *dev)
>>   }
>>   DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15e0, quirk_ryzen_xhci_d3hot);
>>   DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15e1, quirk_ryzen_xhci_d3hot);
>> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1639, quirk_ryzen_xhci_d3hot);
>>   
>>   #ifdef CONFIG_X86_IO_APIC
>>   static int dmi_disable_ioapicreroute(const struct dmi_system_id *d)
>> -- 
>> 2.31.1
>>