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[98.223.182.45]) by smtp.gmail.com with ESMTPSA id n193sm5662253iod.21.2021.01.30.10.42.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 30 Jan 2021 10:42:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=modwiz-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=7xN3NWujt0MZ4nsv093+6CZQ4eRij5kiYXwtNg1RWPc=; b=PdIoDgAQ4rA9KCjUsfE2HvoJ9FJv9RY2tPeFVbHmrrMr74SihQhLuOq8TxWCNRidAD zhu+nPVScrV4mM+U+uARN5A6cTAQxXwMcq1SONj70pVGwk6yg2hX/HBWGXGtX1m5dnHo PkCwIn/8DYEZflLO5FPgLBdN2UUU+TQ/ydvhJ+sMauskJE6qLaMhedKGmGPnxPpdfCf8 mYsClvyvH9NdiDtDfcF1ZJLuvRYBYrJB/nz93L7o7pPRR4xgd9IFVavGmfjizQUXVDMm HdDuTdg/8M1ruNJtUXstxNJX+JpNqtRJslCnjImizdgJZCWz9lH2Yfz3dKbkA/mh5zj0 evnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=7xN3NWujt0MZ4nsv093+6CZQ4eRij5kiYXwtNg1RWPc=; b=N35xndsZXaIJcX66SDy6uyO6RKVC1Sa0vjc2mt0FEiMxu98Tx0nEss43nMe6gMK1sn hTlrCd3t41kfL8wr9TqyhqDUvTG+dlBdiXavM2WLg1FbL4uKQM2BbbwflVH0bBvSqeqR f1qAgVceIjnrdhI9a3iEadhJMGyJ76LWHymnlTd/vwR9++uI0ugl2ESto2MS+uDiB5tR h9uJDdIATXEnuvjCehPkuWDGs1YZT4bFX1MF8ZR5ZSjZcqe95gJLkD1HCHISPrsWNPb1 7q5y7vy9NR2DmcC1uqYctzKHv/gxuI+JSkGRiDXcaWmPaDIBO1+esxspfyJxjH9Mj8HL lwPA== X-Gm-Message-State: AOAM5306ZAa0IrbuIaIXHI+vGPqZsO+uKA3JkX+2YvktHva8GGIU9DzG y3/XOhqQE9h4e6tXLgQngk3Xsw== X-Google-Smtp-Source: ABdhPJxfE9/GMp7qpg8557Tvt8pHTUEI+jvAkCa2ybrT5cz7viIb7kkD+2mTBlObYL2zs8WOZkhhYA== X-Received: by 2002:a05:6638:138e:: with SMTP id w14mr8281564jad.98.1612032153675; Sat, 30 Jan 2021 10:42:33 -0800 (PST) From: Iris Johnson To: Subject: [PATCH] hw/char/exynos4210_uart: Fix missing call to report ready for input Date: Sat, 30 Jan 2021 18:40:17 +0000 Message-Id: <20210130184016.1787097-1-iris@modwiz.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=2607:f8b0:4864:20::d32; envelope-from=iris@modwiz.com; helo=mail-io1-xd32.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Iris Johnson , Igor Mitsyanko , "open list:All patches CC here" , "open list:Exynos" , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" When the frontend device has no space for a read the fd is removed from polling to allow time for the guest to read and clear the buffer. Without the call to qemu_chr_fe_accept_input(), the poll will not be broken out of when the guest has cleared the buffer causing significant IO delays that get worse with smaller buffers. Buglink: https://bugs.launchpad.net/qemu/+bug/1913341 Signed-off-by: Iris Johnson --- hw/char/exynos4210_uart.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/char/exynos4210_uart.c b/hw/char/exynos4210_uart.c index 6361df2ad3..51ba862d0b 100644 --- a/hw/char/exynos4210_uart.c +++ b/hw/char/exynos4210_uart.c @@ -519,6 +519,7 @@ static uint64_t exynos4210_uart_read(void *opaque, hwad= dr offset, s->reg[I_(UTRSTAT)] &=3D ~UTRSTAT_Rx_BUFFER_DATA_READY; res =3D s->reg[I_(URXH)]; } + qemu_chr_fe_accept_input(&s->chr); exynos4210_uart_update_dmabusy(s); trace_exynos_uart_read(s->channel, offset, exynos4210_uart_regname(offset), res); --=20 2.25.1