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Author Topic: libft4222 error  (Read 1492 times)

krispy86

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libft4222 error
« on: January 26, 2018, 02:58:44 PM »

OS - Linux 3.10.87+ using an armv7l processor and Debian based.
Compiler used for the OS and for applications is gcc 4.9.2-10

Specifically Using the FT4222_UnInitialize function.

I've tested with both libft4222-1.2.1.35 and libft4222-linux-1.3.1.120
Tested on the FT4232RQ and FT4232RQ
Edit 3: Actually FT4222HQ

I can run the example code and my own application fine up until it's time to use FT4222_UnInitialize.

If I use FT4222_UnInitialize then the program hangs and never finishes.  I can solve this in a standalone application by only calling FT_Close and never UnInitialize so the program cleans up on exit fine; however, I have created a long running program which periodically needs to open a connection through FTDI, download files, and close the connection so I need to clean up resources rather than just simply close.

The remote end of the connection is constantly creating new files for me to download and if I download, say 400 files each time then after about 5-10 connections I start getting bad data through the connection and the connection starts slowing down immensely to a point where I no longer receive anything from the remote side anymore.

I've done some digging and found that the function hangs at a specific point each time. FT4222_Uninitialize+228
The actual memory address when running is at 0xB6F1D73C

From Objdump
libft4222-1.2.1.35 : Address 0x20744
libft4222-linux-1.3.1.120 : Address 0x1E74C

Edit2: this is a call to _ZN8RxThreadD0Ev7

...
+212 ldr    r2, [r3]
+216 add   r2, r2, #4
+220 ldr    r2, [r2]
+224 mov  r0, r3
+228 blx    r2             -- hangs here
+232 sub   r3, r11, #20
...

If I quit gdb while hanging then I see
[Thread 0xb40ff450 (LWP ####) exited]
__libc_do_syscall () at ../ports/sysdeps/unix/sysv/Linux/arm/libc-do-syscall.S:43

The assembly drops to
0xb6de6540 <__libc_do_syscall>                     push {r7, lr}
0xb6de6542 <__libc_do_syscall+2>                 mov r7, r12
0xb6de6544 <__libc_do_syscall+4>                 svc    0 --- application hangs here
0xb6de6546 <__libc_do_syscall+6>                 pop   {r7, pc}4
0xb6de6548                                                    nop.w
0xb6de654c                                                    nop.w
0xb6de6550 <__fork>                                     b.w 0xb6ddce18
0xb6de6554 <__pthread_mutex_cond_lock>     push {r4,r5,r6,lr}
0xb6de6556 <__pthread_mutex_cond_lock+2> movw r2, #383 ; 0x17f
... mutex function

I also followed the application through GDB using SI all the way through and this is exactly where the program hangs.
r7 is 0xF0.  On my system this is defined as _NR_mq_open. Edit 4: After some more research I found this to be __NR_futex

Anyone have an idea on what can be done here?

Edit 1:
Note that I've tested message queueing using mq_open, mq_send, mq_receive, mq_close using a client server test setup and things work fine.
« Last Edit: January 31, 2018, 01:03:41 PM by krispy86 »
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FTDI Community

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Re: libft4222 error
« Reply #1 on: January 29, 2018, 04:44:08 PM »

Hello,

Would it be possible for you to email your question with an example of your code to support1@ftdichip.com?
Could you also include which revision of the IC you are currently using.

Best Regards,

FTDI Community
« Last Edit: January 29, 2018, 04:47:04 PM by FTDI Community »
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