From: Tony Lindgren <tony@atomide.com>
To: Chen-Yu Tsai <wenst@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
John Ogness <john.ogness@linutronix.de>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
linux-serial@vger.kernel.org, linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] serial: 8250_mtk: Simplify clock sequencing and runtime PM
Date: Tue, 6 Jun 2023 15:13:25 +0300 [thread overview]
Message-ID: <20230606121325.GB14287@atomide.com> (raw)
In-Reply-To: <20230606091747.2031168-1-wenst@chromium.org>
* Chen-Yu Tsai <wenst@chromium.org> [230606 09:19]:
> The 8250_mtk driver's runtime PM support has some issues:
>
> - The bus clock is enabled (through runtime PM callback) later than a
> register write
> - runtime PM resume callback directly called in probe, but no
> pm_runtime_set_active() call is present
> - UART PM function calls the callbacks directly, _and_ calls runtime
> PM API
> - runtime PM callbacks try to do reference counting, adding yet another
> count between runtime PM and clocks
>
> This fragile setup worked in a way, but broke recently with runtime PM
> support added to the serial core. The system would hang when the UART
> console was probed and brought up.
Great, looks like a good for Linux next to me:
Reviewed-by: Tony Lindgren <tony@atomide.com>
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prev parent reply other threads:[~2023-06-06 12:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-06 9:17 [PATCH] serial: 8250_mtk: Simplify clock sequencing and runtime PM Chen-Yu Tsai
2023-06-06 9:36 ` AngeloGioacchino Del Regno
2023-06-06 10:04 ` Chen-Yu Tsai
2023-06-06 10:21 ` Ilpo Järvinen
2023-06-06 10:31 ` Greg Kroah-Hartman
2023-06-06 10:48 ` Ilpo Järvinen
2023-06-06 11:39 ` AngeloGioacchino Del Regno
2023-06-06 12:13 ` Tony Lindgren [this message]
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