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From: Junjie Cao <junjie.cao@intel.com>
To: Shrihari E S <shrihari.s@samsung.com>
Cc: jic23@kernel.org, fan.ni@samsung.com, mst@redhat.com,
	marcel.apfelbaum@gmail.com, dave@stgolabs.net,
	arun.george@samsung.com, dongjoo.seo1@samsung.com,
	s.neeraj@samsung.com, vikash.k5@samsung.com, cpgs@samsung.com,
	gost.dev@samsung.com, linux-cxl@vger.kernel.org,
	linux-pci@vger.kernel.org, qemu-devel@nongnu.org
Subject: Re: [RFC V2 10/10] cxl: Add documentation for CXL UIO support.
Date: Sun, 30 Aug 2026 15:23:30 +0800	[thread overview]
Message-ID: <20260830072330.399591-1-junjie.cao@intel.com> (raw)
In-Reply-To: <124323713.61787732282965.JavaMail.epsvc@epcpadp2new>

Hi Shrihari,

On Wed, 26 Aug 2026 11:04:10 +0530, Shrihari E S wrote:
> +3. **Device 3 Extended Capability**: Enabled via ``x-uio`` on CXL type3

x-uio on its own doesn't get you Dev3: ct3_realize() adds it only when
x-svc and x-256b-flit are set as well.  It does set the HDM UIO bit
with neither of them, which is the asymmetry I raised on 9/10.

> +An example of 3 type3 devices with volatile memory below a switch. All the devices
> +and ports support Unordered IO (UIO) feature which requires Streamlined Virtual Channel

The topology below this doesn't advertise UIO through the switch.  I
ran it -- joined onto single lines, the indented continuations don't
survive a paste -- and the upstream port reads 0x00000382 in its HDM
Decoder Capability register, UIO clear, against 0x00042312 on cxl-rp.
That's the gate in 7/10; worth re-running the example once it's
settled.

Many thanks,
Junjie

  reply	other threads:[~2026-08-30  7:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20260826052014epcas5p11846c6a40fcec4ec4ba441ceb26e5dcc@epcas5p1.samsung.com>
     [not found] ` <20260826053410.1322176-1-shrihari.s@samsung.com>
2026-08-26  5:34   ` [RFC V2 01/10] hw/pci: Refactor flitmode from PCIESlot to PCIEPort Shrihari E S
2026-08-26  5:34   ` [RFC V2 02/10] hw/pci: Move 'x-256b-flit' property from cxl_root_port to pcie_root_port Shrihari E S
2026-08-30  7:20     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 03/10] hw/pci: Add SVC capability and UIO properties to PCIe ports Shrihari E S
2026-08-30  7:20     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 04/10] hw/cxl: Add Streamlined Virtual Channel (SVC) property to CXL ports Shrihari E S
2026-08-26  5:34   ` [RFC V2 05/10] hw/cxl: Wire UIO capability into HDM decoder and DVSEC registers Shrihari E S
2026-08-30  7:21     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 06/10] hw/pci: Add PCIe Streamlined Virtual Channel (SVC) capability Shrihari E S
2026-08-30  7:21     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 07/10] hw/pci: hw/cxl: Wire SVC initialization into port realize functions Shrihari E S
2026-08-30  7:22     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 08/10] hw/pci: Add PCIe Device3 capability support Shrihari E S
2026-08-30  7:22     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 09/10] hw/cxl: Wire SVC and Dev3 capability to CXL Type 3 device Shrihari E S
2026-08-30  7:23     ` Junjie Cao
2026-08-26  5:34   ` [RFC V2 10/10] cxl: Add documentation for CXL UIO support Shrihari E S
2026-08-30  7:23     ` Junjie Cao [this message]
     [not found] <CGME20260826051958epcas5p3db6cf2ef9115168c5d8dcec7bdb9b8c3@epcas5p3.samsung.com>
2026-08-26  5:34 ` [RFC V2 0/9] hw/pci: hw/cxl: Add UIO support in CXL and PCIe stack Shrihari E S
2026-08-30  7:19   ` Junjie Cao

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