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Date: Fri, 5 Jan 2024 09:06:11 +0200
From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Sanath S <sanaths2@amd.com>
Cc: Sanath S <Sanath.S@amd.com>, mario.limonciello@amd.com,
	andreas.noever@gmail.com, michael.jamet@intel.com,
	YehezkelShB@gmail.com, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [Patch v2 2/2] thunderbolt: Teardown tunnels and reset
 downstream ports created by boot firmware
Message-ID: <20240105070611.GM2543524@black.fi.intel.com>
References: <866cb714-b9a8-a7d4-4c59-6ba771ef325f@amd.com>
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 <c433f29b-597c-b6d6-aa48-2b84a26dc623@amd.com>
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 <20231218122312.GE1074920@black.fi.intel.com>
 <997f2a94-66d9-fb95-8f75-46d61937f7e8@amd.com>
 <20231218131840.GH1074920@black.fi.intel.com>
 <0fd5c09f-1cf2-8813-a8f9-1bd856e3a298@amd.com>
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In-Reply-To: <558fb39a-470d-16e3-0043-510e6b4b3f8e@amd.com>

On Thu, Jan 04, 2024 at 10:19:20PM +0530, Sanath S wrote:
> 
> On 12/19/2023 5:56 PM, Mika Westerberg wrote:
> > On Tue, Dec 19, 2023 at 02:41:08PM +0530, Sanath S wrote:
> > > On 12/18/2023 6:48 PM, Mika Westerberg wrote:
> > > > On Mon, Dec 18, 2023 at 06:35:13PM +0530, Sanath S wrote:
> > > > > On 12/18/2023 5:53 PM, Mika Westerberg wrote:
> > > > > > On Mon, Dec 18, 2023 at 01:31:51PM +0200, Mika Westerberg wrote:
> > > > > > > On Mon, Dec 18, 2023 at 04:49:13PM +0530, Sanath S wrote:
> > > > > > > > > The discover part should not do anything (like write the hardware) so
> > > > > > > > > perhaps it is just some timing thing (but that's weird too).
> > > > > > > > > 
> > > > > > > > > I think we should do something like this:
> > > > > > > > > 
> > > > > > > > > 1. Disable all enabled protocol adapters (reset them to defaults).
> > > > > > > > > 2. Clear all protocol adapter paths.
> > > > > > > > > 3. Issue DPR over all enabled USB4 ports.
> > > > > > > > > 
> > > > > > > > > BTW, what you mean "didn't work"?
> > > > > > > > Path activation would go fine after DPR like below:
> > > > > > > > 
> > > > > > > > [   15.090905] thunderbolt 0000:c4:00.5: 0:5 <-> 2:9 (PCI): activating
> > > > > > > > [   15.090932] thunderbolt 0000:c4:00.5: activating PCIe Down path from 0:5
> > > > > > > > to 2:9
> > > > > > > > [   15.091602] thunderbolt 0000:c4:00.5: activating PCIe Up path from 2:9 to
> > > > > > > > 0:5
> > > > > > > > 
> > > > > > > > But, PCIE enumeration doesn't happen (pcie link up will not happen, will not
> > > > > > > > see below logs)
> > > > > > > > [   15.134223] pcieport 0000:00:03.1: pciehp: Slot(0-1): Card present
> > > > > > > > [   15.134243] pcieport 0000:00:03.1: pciehp: Slot(0-1): Link Up
> > > > > > > Okay, what if you like reset the PCIe adapter config spaces back to the
> > > > > > > defaults? Just as an experiment.
> > > > > > If this turns out to be really complex then I guess it is better to do
> > > > > > it like you did originally using discovery but at least it would be nice
> > > > > > to see what the end result of this experiment looks like :)
> > > I feel it's better to go with discover and then reset for now (as v3).
> > > I'll keep this experiment as "to do" and will send out when I crack it down.
> I got what we were missing. It's not required to do a discover_tunnel before
> we tear down.
> 
> We were resetting the downstream port and do a "continue;"
> So, we were not cleaning up its path. Actually we have to cleanup its path
> after DPR.
> 
> After changing it, It works without any tunnel_discover() api's.

Makes sense, good finding.