Modify the uart buffer size

Autonomous Machines Jetson & Embedded Systems Jetson AGX Orin
1

hi nv team,
I enable the serial@3140000 (which is ttyTHS4 in system) in the devicetree.

accroding to the below link

I want to resize the buffer size (xmit_fifo_size) in userspace . but it return failed

I also try to change from the debugfs as follow but it show Permission denied

image
image1920×364 77.2 KB

so how can I modify the uart buffer size ?

3

hello mmcly,

please try modify below via kernel sources.
$public_sources/kernel_src/kernel/kernel-4.9/drivers/staging/fwserial/fwserial.h

 /* tuning parameters */
#define FWTTY_PORT_TXFIFO_LEN	4096
4

thx @JerryChang
for me, What I want to change is the size of rx fifo. Another detail is the xmit_fifo_size I read from the system is 36, which is different from the param FWTTY_PORT_TXFIFO_LEN

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image715×82 7.7 KB

5

hello mmcly,

could you please try revise the definition as following,
$public_sources/kernel_src/kernel/kernel-5.10/drivers/tty/serial/serial-tegra.c

#define TEGRA_UART_FIFO_SIZE                    36

please recompile kernel sources and updating the kernel image for confirmation.
thanks

7

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