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[3.110.210.194]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-36a428af91bsm10889097eec.8.2026.10.30.17.42.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Oct 2026 17:42:26 -0700 (PDT) From: Samarth Narang To: Krzysztof Kozlowski , Peter Griffin , Greg Kroah-Hartman , Jiri Slaby Cc: Marek Szyprowski , Alim Akhtar , linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Samarth Narang Subject: [PATCH 1/2] tty: serial: samsung: pause the RX DMA channel in stop_rx Date: Sat, 31 Oct 2026 00:42:16 +0000 Message-Id: <20261031004217.3340610-2-samarth.colleges@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261031004217.3340610-1-samarth.colleges@gmail.com> References: <20261031004217.3340610-1-samarth.colleges@gmail.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261030_174227_850839_F54B3189 X-CRM114-Status: GOOD ( 13.68 ) X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 In s3c24xx_serial_stop_rx(), the driver pauses dma->tx_chan before reading the residue of the RX transfer on dma->rx_chan to determine how many bytes have been received. Since pausing the TX channel does not stop RX DMA, additional bytes may arrive before the RX channel is terminated, causing them to be omitted from the data passed to the tty. This also unnecessarily pauses an active TX transfer, which the driver does not subsequently resume. Pause the RX channel instead, following the existing handling in s3c24xx_serial_rx_chars_dma() on the RX timeout path. Fixes: b543c301c2c5 ("serial: samsung: add DMA support for RX") Link: https://lore.kernel.org/r/20261030162334.3000737-1-samarth.colleges@gmail.com Assisted-by: LLM Signed-off-by: Samarth Narang --- drivers/tty/serial/samsung_tty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index 4eeef149b..2f6c69bec 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -553,7 +553,7 @@ static void s3c24xx_serial_stop_rx(struct uart_port *port) ourport->rx_enabled = 0; } if (dma && dma->rx_chan) { - dmaengine_pause(dma->tx_chan); + dmaengine_pause(dma->rx_chan); dma_status = dmaengine_tx_status(dma->rx_chan, dma->rx_cookie, &state); if (dma_status == DMA_IN_PROGRESS || -- 2.34.1