Re: [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled

From: "Christian König" <christian.koenig@amd.com>
To: Matt Fagnani <matt.fagnani@bell.net>, Jason Gunthorpe <jgg@nvidia.com>
Cc: Baolu Lu <baolu.lu@linux.intel.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	"Pan, Xinhui" <Xinhui.Pan@amd.com>,
	Vasant Hegde <vasant.hegde@amd.com>,
	Thorsten Leemhuis <regressions@leemhuis.info>,
	Joerg Roedel <jroedel@suse.de>,
	"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
	LKML <linux-kernel@vger.kernel.org>,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	amd-gfx@lists.freedesktop.org
Subject: Re: [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled
Date: Wed, 11 Jan 2023 09:35:16 +0100	[thread overview]
Message-ID: <08f2f79f-e79f-f2d8-2fa8-2cfd59004507@amd.com> (raw)
In-Reply-To: <134da31d-2cf4-431f-2739-aa2940087245@bell.net>

Hi Matt,

after reading a bit into the topic I think I know what's going on here.

The assumption that you need ACS to enable PASID handling is simply 
incorrect.

Going to send a revert of the offending patch with an in deep 
description of the problem.

Thanks,
Christian.

Am 10.01.23 um 21:51 schrieb Matt Fagnani:
> Christian,
>
> I'm attaching the output of sudo lspci -vvvv. I'm not sure what 
> $bus_id is in this case. I guess it might be 00 in 00:00.0. I attached 
> the dmesg from previous boots with 6.2-rc1 at 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.kernel.org%2Fshow_bug.cgi%3Fid%3D216865%23c2&data=05%7C01%7Cchristian.koenig%40amd.com%7Cc14ca7b3ead040ee279f08daf34c8687%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638089808663927196%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=iFHmme68OeqRpw7zlSPp%2F1mB95DKCR%2FTAsjTcjT6S1s%3D&reserved=0 
> as I mentioned at 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F52583644-d875-a454-7288-8b00ea0566ae%40bell.net%2F&data=05%7C01%7Cchristian.koenig%40amd.com%7Cc14ca7b3ead040ee279f08daf34c8687%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638089808663927196%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=j8ZppuXkhw4dD9HS6OwsvulZaV1R3W8Hu%2BW11%2BxMCuE%3D&reserved=0 
> and 6.2-rc2 + Vasant's patch with rd.driver.blacklist=amdgpu on the 
> kernel command line at 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2Fff26929d-9fb0-3c85-2594-dc2937c1ba9a%40bell.net%2F&data=05%7C01%7Cchristian.koenig%40amd.com%7Cc14ca7b3ead040ee279f08daf34c8687%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638089808663927196%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=i6fxlEn74v86MnFfgCmtYQ2JCql0sVsimZqioBiDyPk%3D&reserved=0 
> I'm using the Radeon R5 integrated GPU which is called Wani in lspci 
> and Carrizo in dmesg. The CPU is AMD A10-9620P which is Bristol Ridge 
> or Excavator+ according to 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FList_of_AMD_accelerated_processing_units&data=05%7C01%7Cchristian.koenig%40amd.com%7Cc14ca7b3ead040ee279f08daf34c8687%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638089808664083434%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=Ywp7MnbjYMeyXGGNFHOyn2A45IZSLIsShkIPEC4GB48%3D&reserved=0 
> I'm using the internal Elan touchscreen in the laptop. I'm not using 
> the HDMI port for an external monitor or audio which I think is called 
> Kabini HDMI/DP Audio in lspci
>
> Thanks,
>
> Matt
>
> On 1/10/23 08:56, Christian König wrote:
>> Am 10.01.23 um 14:51 schrieb Jason Gunthorpe:
>>> On Tue, Jan 10, 2023 at 02:45:30PM +0100, Christian König wrote:
>>>
>>>> Since this is a device integrated in the CPU it could be that the 
>>>> ACS/ATS
>>>> functionalities are controlled by the BIOS and can be enabled/disabled
>>>> there. But this should always enable/disable both.
>>> This sounds like a GPU driver bug then, it should tolerate PASID being
>>> unavailable because of BIOS issues/whatever and not black screen on
>>> boot?
>>
>> Yeah, potentially. Could I get a full "sudo lspci -vvvv -s $bus_id" + 
>> dmesg of that device?
>>
>> Thanks,
>> Christian.
>>
>>>
>>> Jason
>>