linux-kernel - Re: [PATCH v2] xhci: Convert xhci_handshake() to use readl_poll_timeout

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Message-ID: <20190429200541.GA116440@google.com>
Date:   Mon, 29 Apr 2019 14:05:41 -0600
From:   Raul Rangel <rrangel@...omium.org>
To:     Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     linux-usb@...r.kernel.org, Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] xhci: Convert xhci_handshake() to use
 readl_poll_timeout_atomic()

On Thu, Feb 07, 2019 at 05:48:16PM -0800, Andrey Smirnov wrote:
> Xhci_handshake() implements the algorithm already captured by
> readl_poll_timeout_atomic(). Convert the former to use the latter to
> avoid repetition.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Tested-by: Raul E Rangel <rrangel@...omium.org>
Reviewed-by: Raul E Rangel <rrangel@...omium.org>

This fixes a bug on the AMD Stoneyridge platform. usleep(1) sometimes
takes over 10ms. This means a 5 second timeout can easily take over 15
seconds which will trigger the watchdog and reboot the system.

Thanks for the patch.