From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [RFC PATCH v4] tty: pl011: Avoid spuriously stuck-off interrupts Date: Thu, 26 Apr 2018 11:54:40 +0100 Message-ID: <1524740081-4979-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: linux-arm-kernel@lists.infradead.org Cc: Peter Maydell , Linus Walleij , Wei Xu , Russell King , linux-serial@vger.kernel.org List-Id: linux-serial@vger.kernel.org This is an update to a previous RFC v3 [1], to fix a problem observed by the qemu community that causes serial input to hang when booting a simulated system with data already queued in the UART FIFO [2]. RFC v3 did not solve the problem by itself, due to the problem being triggered again in pl011_enable_interrupts() after working around it in pl011_hwinit(). See the updated commit message in the patch for details. This patch is intended to supersede the previous RFCs, so please test _without_ RFC v2 (or 3) applied. If you can, please: a) Check that you can still reproduce the bug on mainline without this patch. b) Check whether this patch fixes the problem. Cheers ---Dave [1] [RFC PATCH v3] tty: pl011: Avoid spuriously stuck-off interrupts http://lists.infradead.org/pipermail/linux-arm-kernel/2018-April/573120.html [2] [Qemu-devel] [Qemu-arm] [PATCH] pl011: do not put into fifo before enabled the interruption https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg06446.html Dave Martin (1): tty: pl011: Avoid spuriously stuck-off interrupts drivers/tty/serial/amba-pl011.c | 10 ++++++++++ 1 file changed, 10 insertions(+) -- 2.1.4