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Message-ID: <9f42f88f-26bc-1e82-03a0-659c85c40469@i2se.com>
Date:   Thu, 22 Dec 2022 13:19:54 +0100
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Subject: Re: [PATCH v2 1/2] usb: misc: onboard_usb_hub: Don't create platform
 devices for DT nodes without 'vdd-supply'
Content-Language: en-US
To:     Matthias Kaehlcke <mka@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        stable@vger.kernel.org, Douglas Anderson <dianders@chromium.org>,
        Ravi Chandra Sadineni <ravisadineni@chromium.org>
References: <20221222022605.v2.1.If5e7ec83b1782e4dffa6ea759416a27326c8231d@changeid>
From:   Stefan Wahren <stefan.wahren@i2se.com>
In-Reply-To: <20221222022605.v2.1.If5e7ec83b1782e4dffa6ea759416a27326c8231d@changeid>
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Precedence: bulk

Am 22.12.22 um 03:26 schrieb Matthias Kaehlcke:
> The primary task of the onboard_usb_hub driver is to control the
> power of an onboard USB hub. The driver gets the regulator from the
> device tree property "vdd-supply" of the hub's DT node. Some boards
> have device tree nodes for USB hubs supported by this driver, but
> don't specify a "vdd-supply". This is not an error per se, it just
> means that the onboard hub driver can't be used for these hubs, so
> don't create platform devices for such nodes.
>
> This change doesn't completely fix the reported regression. It
> should fix it for the RPi 3 B Plus and boards with similar hub
> configurations (compatible DT nodes without "vdd-supply"), boards
> that actually use the onboard hub driver could still be impacted
> by the race conditions discussed in that thread. Not creating the
> platform devices for nodes without "vdd-supply" is the right
> thing to do, independently from the race condition, which will
> be fixed in future patch.
>
> Fixes: 8bc063641ceb ("usb: misc: Add onboard_usb_hub driver")
> Link: https://lore.kernel.org/r/d04bcc45-3471-4417-b30b-5cf9880d785d@i2se.com/
> Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>