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tbird20d / grabserial

Grabserial - python-based serial dump and timing program - good for embedded Linux development
GNU General Public License v2.0
198 stars 79 forks source link

Using -c <command> or --command="<command>" #8

Closed wojt closed 8 years ago

wojt commented 9 years ago

Hi,

I noticed that for command to work properly I had to change the code

from:

if command:
    sd.write(command + "\n")
    sd.flush()

to:

if command:
    sd.write(command + "\r")
    sd.flush()

Thanks, Wojtek

tbird20d commented 9 years ago

Are you, by chance, using this on Windows?

wojt commented 9 years ago

Hi,

Nope, I'm using it on Ubuntu Linux. I'm working with Intel Galileo 2 board. Grabserial uses command syntax to interface with UEFI shell (EDK II).

Wojtek

wojt commented 9 years ago

This may be related to UEFI shell. Its syntax is a little bit Window-ish. I'm not sure.

wojt commented 9 years ago

Yup, sorry for spamming you with false issues.

I found this: "Also note that UEFI uses CRLF line terminators (\r\n) instead of just LF (\n), and when we use native EFI functions, there is no layer which reinterprets LF to CRLF. Normally, applications use additional library called EFILIB which does the LF->CRLF transform."

Here: http://x86asm.net/articles/uefi-programming-first-steps/

So it's just UEFI's shell issue. So unless you add a switch for grabserial to pick what line endings are used, then nothing can be done about it.

tbird20d commented 9 years ago

From: wojt notifications@github.com To: tbird20d/grabserial grabserial@noreply.github.com Cc: Tim Bird tbird20d@yahoo.com Sent: Friday, March 27, 2015 8:44 AM Subject: Re: [grabserial] Using -c or --command="" (#8)

Yup, sorry for spamming you with false issues. I found this: "Also note that UEFI uses CRLF line terminators (\r\n) instead of just LF (\n), and when we use native EFI functions, there is no layer which reinterprets LF to CRLF. Normally, applications use additional library called EFILIB which does the LF->CRLF transform." Here: http://x86asm.net/articles/uefi-programming-first-steps/ So it's just UEFI's shell issue. So unless you add a switch for grabserial to pick what line endings are used, then nothing can be done about it.

I thought about this over the weekend, and I had two ideas: 1) just use \r\n always, and see if it's an issue for other shells or platforms. 2) try to automatically detect if we're in a UEFI shell, or alternatively in a shell that needs a '\r'. I might be able to run a little test program to detect that.

I would like to avoid adding a switch if possible.

Let me know what you think. -- Tim