From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 383E82D5932 for ; Tue, 8 Sep 2026 14:29:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788877789; cv=none; b=XL9qWI3UA5KHuuXd7q97+I1fpNNZq0P+N3/yQPaWXPL8rqzplnf95EJTql2uDUMV4Wh9VYS+zGPkxsnNofFLZilBHU/XEULRsTGNP9uFlGZEpIp5xy1vOlVmFZIdwP3rwijpsqcs4pe1q5+wwPTOpcx442ZNO3AMdSnINe+LcQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788877789; c=relaxed/simple; bh=W4qIcXY5SCPf0xGkvlD47BBUS2OqiYWQ4+rcOhMjWvk=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=bIwYRF3PvBI9UALW7lMBeGGnJkEUatLssa8+aux1q9GfXvdlM2ABLu/2lGMIo6qo8vorqQfM9hIs2/r9sY/2EJVqEeVOyxXTpPhCUL+uT5j6P0VVxudrmnUTd/wvbS6o6qx+4UY2Y2+by8Cuc+Z4XX0ppsZuFEdmXR1gwK5C614= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4FF31F00A3A; Tue, 8 Sep 2026 14:29:42 +0000 (UTC) From: sashiko-bot@kernel.org Subject: Re: [PATCH v3] serial: 8250_dw: Prefer SRBR in bogus RX timeout workaround if available Reply-To: sashiko-reviews@lists.linux.dev To: "Yicong Yang" Cc: linux-serial@vger.kernel.org In-Reply-To: <20260908141524.20302-1-yang.yicong@picoheart.com> References: <20260908141524.20302-1-yang.yicong@picoheart.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 08 Sep 2026 14:29:37 +0000 Message-Id: <20260908142942.E4FF31F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: Pre-existing issues: - [High] Calling pm_runtime_enable() after serial port registration leads t= o circular dependencies and blocked tasks during device probe. -- commit fbed7674eea9b0cab135230c5f02f518f9590574 Author: Yicong Yang serial: 8250_dw: Prefer SRBR in bogus RX timeout workaround if available This commit updates the DesignWare 8250 UART driver to use the Shadow=20 Receive Buffer Register (SRBR) instead of the standard RBR for bogus=20 reads during RX timeouts. This avoids potential hardware errors on=20 platforms that do not support standard RBR reads in this state. Link: https://lore.kernel.org/linux-serial/20260907074035.77796-1-yang.yico= ng@picoheart.com/ Link: https://lore.kernel.org/linux-serial/20260629075510.32854-1-yang.yico= ng@picoheart.com/ > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/= 8250_dw.c > index 51d026f20825a..b8a0bca8b536f 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c [Severity: High] This isn't a bug introduced by this patch, but while reviewing the changes= =20 to this file, I noticed a pre-existing issue regarding runtime PM=20 initialization in the probe sequence. Does dw8250_probe() register the serial port before enabling runtime PM? When serial8250_register_8250_port() is called, it synchronously invokes uart_add_one_port(). This can trigger the dw8250_do_pm() callback: dw8250_do_pm() { if (!state) pm_runtime_get_sync(port->dev); ... } If this callback fires before pm_runtime_enable() is executed at the end=20 of dw8250_probe(), it will attempt to use runtime PM APIs on an=20 uninitialized device. Could this circular dependency lead to blocked tasks and hung worker=20 threads during device probe? [ ... ] --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260908141524.2030= 2-1-yang.yicong@picoheart.com?part=3D1