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authorIris Johnson2021-01-30 19:40:17 +0100
committerPeter Maydell2021-02-02 18:00:54 +0100
commitf2c0fb93a44972a96f93510311c93ff4c2c6fab5 (patch)
tree5f935e7f6a0ea80500ab9c0671686a25da9db9ff /hw/char
parenthw/char/exynos4210_uart: Fix buffer size reporting with FIFO disabled (diff)
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hw/char/exynos4210_uart: Fix missing call to report ready for input
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>
Diffstat (limited to 'hw/char')
-rw-r--r--hw/char/exynos4210_uart.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/hw/char/exynos4210_uart.c b/hw/char/exynos4210_uart.c
index 9b21d201b3..80d401a379 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);