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Fri, 24 Nov 2023 10:24:18 +0000 (GMT) From: =?utf-8?Q?Alex_Benn=C3=A9e?= To: Peter Maydell Cc: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Gavin Shan , Paolo Bonzini , Mark Cave-Ayland , Evgeny Iakovlev , qemu-arm@nongnu.org Subject: Re: [PATCH-for-8.2 v4 00/10] hw/char/pl011: Implement TX (async) FIFO to avoid blocking the main loop In-Reply-To: (Peter Maydell's message of "Mon, 13 Nov 2023 13:11:22 +0000") References: <20231109192814.95977-1-philmd@linaro.org> <4ffed8f5-6624-4488-a74f-567cbd926b78@linaro.org> User-Agent: mu4e 1.11.25; emacs 29.1 Date: Fri, 24 Nov 2023 10:24:18 +0000 Message-ID: <87jzq7cuul.fsf@draig.linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::429; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x429.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Maydell writes: > On Thu, 9 Nov 2023 at 20:59, Philippe Mathieu-Daud=C3=A9 wrote: >> >> Hi Peter, >> >> On 9/11/23 20:29, Peter Maydell wrote: >> > On Thu, 9 Nov 2023 at 19:28, Philippe Mathieu-Daud=C3=A9 wrote: >> >> >> >> Missing review: #10 >> >> >> >> Hi, >> >> >> >> This series add support for (async) FIFO on the transmit path >> >> of the PL011 UART. >> > >> > Hi; what's the rationale for the "for-8.2" targeting here? >> > What bug are we fixing? >> >> The bug is on Trusted Substrate when the ZynqMP machine is used: >> https://linaro.atlassian.net/browse/TRS-149?focusedCommentId=3D149574 > > And have we confirmed that the async FIFO support fixes that problem? > That bug report seems to have mostly just speculation in it that > maybe this XXX comment is why... I've been fighting with numerous issues with the TRS build over the last week so I can confirm I have seen a) a lock up with pl011_write blocking everything under the BQL because data wasn't read fast enough and b) the problem goes away with Philippe's patches. So have a: Tested-by: Alex Benn=C3=A9e for the series. > > -- PMM --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro