On 25. 01. 22, 10:08, Jiri Slaby wrote:
On 25. 01. 22, 9:39, Jon Hunter wrote:
On 29/10/2021 21:14, wander@xxxxxxxxxx wrote:
From: Wander Lairson Costa <wander@xxxxxxxxxx>
Note: I am using a small test app + driver located at [0] for the
problem description. serco is a driver whose write function dispatches
to the serial controller. sertest is a user-mode app that writes n bytes
to the serial console using the serco driver.
...
Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx>
On the current mainline and -next branches, I have noticed that the
serial output on many of our Tegra boards is corrupted and so
parsing the serial output is failing.
Before this change the serial console would appear as follows ...
[ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd071]
[ 0.000000] Linux version 5.16.0-rc6-00091-gadbfddc757ae
(jonathanh@jonathanh-vm-01) (aarch64-linux-gnu-gcc (Linaro GCC
6.4-2017.08) 6.4.1 20170707, GNU ld (Linaro_Binutils-2017.08)
2.27.0.20161019) #15 SMP PREEMPT Tue Jan 25 00:15:25 PST 2022
[ 0.000000] Machine model: NVIDIA Jetson TX1 Developer Kit
And now I see ...
[ 0.000000] Booting Linux on physicalfd071]
[ 0.000000] Linux version 5.16.0-rc6-athanh@j-linux-g017.08)
Linaro_B20161019n 25 00:[ 0.000000] Machine model: NVIDIA Jet[
0.000000] efi: UEFI not found.
[ 0.000000] NUMA: No NUMA configurati[ 0.000000] NUMA: Faking a
node at [m00000001[ 0.000000] NUMA: NODE_DATA [mem 0x17[
0.000000] Zone ranges:
Bisecting is pointing to this commit. Let me know if there are any
tests I can run. Otherwise we may need to disable this at least
for Tegra.
The test is bogus:
use_fifo = (up->capabilities & UART_CAP_FIFO) &&
port->fifosize > 1 &&
(serial_port_in(port, UART_FCR) & UART_FCR_ENABLE_FIFO)
FCR is write only. Reading it, one gets IIR contents.
In particular, the test is checking whether there is no interrupt
pending (UART_FCR_ENABLE_FIFO == UART_IIR_NO_INT). So it oscillates
between use_fifo and not, depending on the interrupt state of the chip.
Could you change it into something like this:
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3396,7 +3396,7 @@ void serial8250_console_write(struct
uart_8250_port *up, const char *s,
use_fifo = (up->capabilities & UART_CAP_FIFO) &&
port->fifosize > 1 &&
- (serial_port_in(port, UART_FCR) & UART_FCR_ENABLE_FIFO) &&
+ (up->fcr & UART_FCR_ENABLE_FIFO) &&
/*
* After we put a data in the fifo, the controller will
send
* it regardless of the CTS state. Therefore, only use fifo
And see whether it fixes the issue. Anyway, of what port type is the
serial port (what says dmesg/setserial about that)?
thanks,
--
js
suse labs
