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From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-devel@nongnu.org
Subject: [PULL 03/21] hw/char/exynos4210_uart: Fix missing call to report ready for input
Date: Tue,  2 Feb 2021 17:54:59 +0000	[thread overview]
Message-ID: <20210202175517.28729-4-peter.maydell@linaro.org> (raw)
In-Reply-To: <20210202175517.28729-1-peter.maydell@linaro.org>

From: Iris Johnson <iris@modwiz.com>

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 <iris@modwiz.com>
Message-id: 20210130184016.1787097-1-iris@modwiz.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 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 9b21d201b34..80d401a3795 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, hwaddr offset,
             s->reg[I_(UTRSTAT)] &= ~UTRSTAT_Rx_BUFFER_DATA_READY;
             res = 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);
-- 
2.20.1



  parent reply	other threads:[~2021-02-02 18:03 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 17:54 [PULL 00/21] target-arm queue Peter Maydell
2021-02-02 17:54 ` [PULL 01/21] hw/intc/arm_gic: Allow to use QTest without crashing Peter Maydell
2021-02-02 17:54 ` [PULL 02/21] hw/char/exynos4210_uart: Fix buffer size reporting with FIFO disabled Peter Maydell
2021-02-02 17:54 ` Peter Maydell [this message]
2021-02-02 17:55 ` [PULL 04/21] hw/arm/smmuv3: Fix addr_mask for range-based invalidation Peter Maydell
2021-02-02 17:55 ` [PULL 05/21] hw/ssi: imx_spi: Use a macro for number of chip selects supported Peter Maydell
2021-02-02 17:55 ` [PULL 06/21] hw/ssi: imx_spi: Remove imx_spi_update_irq() in imx_spi_reset() Peter Maydell
2021-02-02 17:55 ` [PULL 07/21] hw/ssi: imx_spi: Remove pointless variable initialization Peter Maydell
2021-02-02 17:55 ` [PULL 08/21] hw/ssi: imx_spi: Rework imx_spi_reset() to keep CONREG register value Peter Maydell
2021-02-02 17:55 ` [PULL 09/21] hw/ssi: imx_spi: Rework imx_spi_read() to handle block disabled Peter Maydell
2021-02-02 17:55 ` [PULL 10/21] hw/ssi: imx_spi: Rework imx_spi_write() " Peter Maydell
2021-02-02 17:55 ` [PULL 11/21] hw/ssi: imx_spi: Disable chip selects when controller is disabled Peter Maydell
2021-02-02 17:55 ` [PULL 12/21] hw/ssi: imx_spi: Round up the burst length to be multiple of 8 Peter Maydell
2021-02-02 17:55 ` [PULL 13/21] hw/ssi: imx_spi: Correct the burst length > 32 bit transfer logic Peter Maydell
2021-02-02 17:55 ` [PULL 14/21] hw/ssi: imx_spi: Correct tx and rx fifo endianness Peter Maydell
2021-02-02 17:55 ` [PULL 15/21] hw/intc/arm_gic: Fix interrupt ID in GICD_SGIR register Peter Maydell
2021-02-02 17:55 ` [PULL 16/21] hw/arm/stm32f405_soc: Add missing dependency on OR_IRQ Peter Maydell
2021-02-02 17:55 ` [PULL 17/21] hw/arm/exynos4210: " Peter Maydell
2021-02-02 17:55 ` [PULL 18/21] hw/arm/xlnx-versal: Versal SoC requires ZDMA Peter Maydell
2021-02-02 17:55 ` [PULL 19/21] hw/arm/xlnx-versal: Versal SoC requires ZynqMP peripherals Peter Maydell
2021-02-02 17:55 ` [PULL 20/21] hw/net/can: ZynqMP CAN device requires PTIMER Peter Maydell
2021-02-02 17:55 ` [PULL 21/21] hw/arm: Display CPU type in machine description Peter Maydell
2021-02-03  9:22 ` [PULL 00/21] target-arm queue Philippe Mathieu-Daudé
2021-02-03 10:12   ` P J P

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