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From: Lukas Wunner <lukas@wunner.de>
To: Dave Jiang <dave.jiang@intel.com>
Cc: linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org,
	dan.j.williams@intel.com, ira.weiny@intel.com,
	vishal.l.verma@intel.com, alison.schofield@intel.com,
	Jonathan.Cameron@huawei.com, dave@stgolabs.net,
	bhelgaas@google.com
Subject: Re: [PATCH 0/3] PCI: Add Secondary Bus Reset (SBR) support for CXL
Date: Tue, 12 Mar 2024 08:46:05 +0100	[thread overview]
Message-ID: <ZfAIPSy8uih74ZkK@wunner.de> (raw)
In-Reply-To: <20240311204132.62757-1-dave.jiang@intel.com>

On Mon, Mar 11, 2024 at 01:39:52PM -0700, Dave Jiang wrote:
> Patch 1:
> Add check to PCI bus_reset path for CXL device and return with error if "Unmask
> SBR" bit is set to 0. This allows user to realize that SBR is masked for this
> CXL device. However, if the user sets the "Unmask SBR" bit via a tool such as
> setpci, then the bus_reset will proceed.

So is the point of patch 1 only to inform the user that the SBR has
no effect?  Or does the SBR have any negative side effects that you
want to avoid (e.g. due to the config space save/restore)?

If you only want to inform the user, then this functionality could
live in a ->reset_prepare() callback exposed by the cxl subsystem
and the pci subsystem wouldn't have to be touched at all.

Thanks,

Lukas

  parent reply	other threads:[~2024-03-12  7:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-11 20:39 [PATCH 0/3] PCI: Add Secondary Bus Reset (SBR) support for CXL Dave Jiang
2024-03-11 20:39 ` [PATCH 1/3] PCI: Add check for CXL Secondary Bus Reset Dave Jiang
2024-03-12  7:30   ` Lukas Wunner
2024-03-12 21:35     ` Dave Jiang
2024-03-11 20:39 ` [PATCH 2/3] PCI: Create new reset method to force SBR for CXL Dave Jiang
2024-03-12  7:50   ` Lukas Wunner
2024-03-11 20:39 ` [PATCH 3/3] cxl: Add post reset warning if reset is detected as Secondary Bus Reset (SBR) Dave Jiang
2024-03-12  7:46 ` Lukas Wunner [this message]
2024-03-12 21:31   ` [PATCH 0/3] PCI: Add Secondary Bus Reset (SBR) support for CXL Dave Jiang

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