From: Mathias Nyman <mathias.nyman@linux.intel.com>
To: Lovekesh Solanki <lovekeshsolanki00@gmail.com>,
linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Michal Pecio <michal.pecio@gmail.com>,
Mathieu Fluhr <mathieu.fluhr@gmail.com>,
Mario Limonciello <mario.limonciello@amd.com>,
Thorsten Leemhuis <regressions@leemhuis.info>,
stable@vger.kernel.org, greg@kroah.com,
stern@rowland.harvard.edu
Subject: Re: [PATCH v2] usb: hub: use shorter 120ms post resume hold for SS root hubs
Date: Thu, 3 Sep 2026 15:23:24 +0300 [thread overview]
Message-ID: <6813d58b-a939-4ac2-81a4-438781485899@linux.intel.com> (raw)
In-Reply-To: <20260903112903.542719-1-lovekeshsolanki00@gmail.com>
On 9/3/26 14:29, Lovekesh Solanki wrote:
> Holding a USB3 hub PM runtime reference for 200ms at hub resume triggers
> an AMD platform issue. Users running Android adb report crashes after
> adb has been polling and waking up the USB subsystem once a second for
> some time. Vendors are working on a solution. Disabling USB runtime PM
> is one way to prevent this issue, but it is also proven that reducing the
> hold time to 120ms in resume also mitigates it. See Link for more
> details.
>
> Reducing the hold time to 120ms for the USB3 roothub is in itself a valid
> change and optimization, as the current 200ms is excessive: a root hub
> has no upstream suspended hub whose wake propagation needs to be
> accounted for, but still need some time for USB3 link training to
> complete.
>
> Keep the 200ms hold for external hubs that commit 8f5b7e2bec1c
> ("usb: hub: fix detection of high tier USB3 devices behind suspended
> hubs") is intended for.
>
> Reported-by: Mathieu Fluhr <mathieu.fluhr@gmail.com>
> Link: https://lore.kernel.org/all/CAPyJwA_D9qw0T72f8zwM1yKjP+To=maVANbcdsWM7yRmbBxYvw@mail.gmail.com/
> Cc: stable@vger.kernel.org
> Fixes: 8f5b7e2bec1c ("usb: hub: fix detection of high tier USB3 devices behind suspended hubs")
> Signed-off-by: Lovekesh Solanki <lovekeshsolanki00@gmail.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
prev parent reply other threads:[~2026-09-03 12:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-03 11:29 [PATCH v2] usb: hub: use shorter 120ms post resume hold for SS root hubs Lovekesh Solanki
2026-09-03 12:23 ` Mathias Nyman [this message]
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