Zev Weiss d6c4fc0d90 serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type ... [ Upstream commit a603ca60ce ] Commit 54da3e381c ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to set up register mapping") fixed a bug that had, as a side-effect, prevented the 8250_aspeed_vuart driver from enabling the VUART's FIFOs. However, fixing that (and hence enabling the FIFOs) has in turn revealed what appears to be a hardware bug in the ASPEED VUART in which the host-side THRE bit doesn't get if the BMC-side receive FIFO trigger level is set to anything but one byte. This causes problems for polled-mode writes from the host -- for example, Linux kernel console writes proceed at a glacial pace (less than 100 bytes per second) because the write path waits for a 10ms timeout to expire after every character instead of being able to continue on to the next character upon seeing THRE asserted. (GRUB behaves similarly.) As a workaround, introduce a new port type for the ASPEED VUART that's identical to PORT_16550A as it had previously been using, but with UART_FCR_R_TRIG_00 instead to set the receive FIFO trigger level to one byte, which (experimentally) seems to avoid the problematic THRE behavior. Fixes: 54da3e381c ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to set up register mapping") Tested-by: Konstantin Aladyshev <aladyshev22@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Link: https://lore.kernel.org/r/20220211004203.14915-1-zev@bewilderbeest.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-04-08 14:23:45 +02:00
..
asm-generic	aio: fix use-after-free due to missing POLLFREE handling	2021-12-14 10:57:15 +01:00
drm	drm/tegra: Changes for v5.15-rc1	2021-08-26 13:05:19 +10:00
linux	serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type	2022-04-08 14:23:45 +02:00
misc	habanalabs: fix resetting args in wait for CS IOCTL	2021-09-29 12:18:48 +03:00
mtd
rdma	Merge branch 'sg_nents' into rdma.git for-next	2021-08-30 09:49:59 -03:00
scsi	scsi: fc: Add EDC ELS definition	2021-08-24 22:56:33 -04:00
sound	ASoC: hdmi-codec: Fix OOB memory accesses	2022-02-08 18:34:03 +01:00
video
xen
Kbuild