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From: Mathias Nyman <mathias.nyman@linux.intel.com>
To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc: "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
	"michal.pecio@gmail.com" <michal.pecio@gmail.com>,
	"oneukum@suse.com" <oneukum@suse.com>,
	"niklas.neronin@linux.intel.com" <niklas.neronin@linux.intel.com>
Subject: Re: [RFC PATCH 1/2] xhci: prevent automatic endpoint restart after stall or error
Date: Wed, 25 Mar 2026 11:38:43 +0200	[thread overview]
Message-ID: <0f38e10d-ecac-4beb-ad2c-3a42c2546c3c@linux.intel.com> (raw)
In-Reply-To: <20260325015110.v4r5smfvdd62fcua@synopsys.com>

On 3/25/26 03:52, Thinh Nguyen wrote:
> On Mon, Mar 23, 2026, Mathias Nyman wrote:
>> Avoid automatically restarting bulk or interrupt transfers after a
>> URB is given back due to stall or error.
>>
>> Introduce a 'TD_TAINTED' state for pending TDs queued on a endpoint when
>> it halted. The actual TD the endpoint halted on is marked TD_HALTED,
>> and its URB is given back with proper EPROTO or EPIPE error code.
>>
>> Don't automatically restart an endpoint if the next queued TD after
>> the TD_HALTED one is marked tainted.
> 
> Sounds good for -EPROTO, but will a clear-halt ring the corresponding
> the endpoint's doorbell for STALL endpoint?
> 

With this change xhci would not restart the stalled endpoint after a clear-halt
request. The first usb_enqueue() call after clear-halt would start it.

Could make sense to restart the endpoint after a clear-halt, and just add a small
debug message if the next queued URB is marked 'tainted'.

Thanks for the feedback
Mathias


  reply	other threads:[~2026-03-25  9:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-23 12:25 [RFC PATCH 0/2] fix xhci endpoint restart at EPROTO Mathias Nyman
2026-03-23 12:25 ` [RFC PATCH 1/2] xhci: prevent automatic endpoint restart after stall or error Mathias Nyman
2026-03-25  1:52   ` Thinh Nguyen
2026-03-25  9:38     ` Mathias Nyman [this message]
2026-03-26  1:19       ` Thinh Nguyen
2026-03-26 11:25         ` Mathias Nyman
2026-03-26 23:24           ` Thinh Nguyen
2026-03-23 12:25 ` [RFC PATCH 2/2] xhci: Ensure URB is given back when endpoint halts on a multi-TD URB Mathias Nyman

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