Zev Weiss a603ca60ce serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type ... 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>		2022-02-21 19:48:34 +01:00
..
acpi	USB/Thunderbolt changes for 5.17-rc1	2022-01-12 11:27:57 -08:00
asm-generic	bitmap patches for 5.17-rc1	2022-01-23 06:20:44 +02:00
clocksource
crypto	lib/crypto: blake2s: avoid indirect calls to compression function for Clang CFI	2022-02-04 19:22:32 +01:00
drm	Merge tag 'drm-msm-next-2021-12-26' of ssh://gitlab.freedesktop.org/drm/msm into drm-next	2021-12-29 14:02:44 +10:00
dt-bindings	Fixes for omaps	2022-02-07 17:42:44 +01:00
keys	keys: X.509 public key issuer lookup without AKID	2022-01-09 00:18:42 +02:00
kunit	kunit: replace kernel.h with the necessary inclusions	2022-01-20 08:52:54 +02:00
kvm	RISCV:	2022-01-16 16:15:14 +02:00
linux	Linux 5.17-rc4	2022-02-14 09:06:09 +01:00
math-emu
media
memory
misc
net	net: fix a memleak when uncloning an skb dst and its metadata	2022-02-09 11:41:47 +00:00
pcmcia
ras	mm/hwpoison: remove MF_MSG_BUDDY_2ND and MF_MSG_POISONED_HUGE	2022-01-15 16:30:31 +02:00
rdma	RDMA/core: Calculate UDP source port based on flow label or lqpn/rqpn	2022-01-07 19:34:01 -04:00
scsi	Merge branch 'akpm' (patches from Andrew)	2022-01-22 11:28:23 +02:00
soc	Networking changes for 5.17.	2022-01-10 19:06:09 -08:00
sound	ASoC: Fixes for v5.17	2022-02-01 16:52:54 +01:00
target
trace	Tracing fixes for 5.17-rc1:	2022-01-28 19:30:35 +02:00
uapi	serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type	2022-02-21 19:48:34 +01:00
vdso
video
xen	xen: xenbus_dev.h: delete incorrect file name	2022-02-03 08:16:32 +01:00