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[v3,0/2] serial: 8250: Mitigate Tx stall risk for Aspeed VUARTs

Message ID 20210520021334.497341-1-andrew@aj.id.au (mailing list archive)
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Series serial: 8250: Mitigate Tx stall risk for Aspeed VUARTs | expand

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Andrew Jeffery May 20, 2021, 2:13 a.m. UTC 
Hello,

Briefly, the series works around a hardware race condition in the Tx path for
Aspeed virtual UARTs. A write burst to THR on the APB interface may provoke a
transfer stall where LSR[DR] on the LPC interface remains clear despite the
presence of data in the Rx FIFO.

v3 addresses comments from Jiri on v2. v2 can be found here:

https://lore.kernel.org/lkml/20210519000704.3661773-1-andrew@aj.id.au/

The documentation patch that fell out of the discussion of patch 2 of v2 can be
found here:

https://lore.kernel.org/lkml/20210520015704.489737-1-andrew@aj.id.au/T/#u

Please review!

Andrew

Andrew Jeffery (2):
  serial: 8250: Add UART_BUG_TXRACE workaround for Aspeed VUART
  serial: 8250: Use BIT(x) for UART_{CAP,BUG}_*

 drivers/tty/serial/8250/8250.h              | 32 +++++++++++----------
 drivers/tty/serial/8250/8250_aspeed_vuart.c |  1 +
 drivers/tty/serial/8250/8250_port.c         | 12 ++++++++
 3 files changed, 30 insertions(+), 15 deletions(-)