Suggestion: allow brute forcing ddcutil commands to "fix" issues on Samsung displays

[pacjo]

Hi there, this one will require some explanation.
So I have an older Samsung monitor, specifically 24" CF390. The issue is that DDC/CI communication works sporadically (it's just nowhere near consistent) (similar issue here).

So, the fix:
If you try enough times, at some point, you will get a proper output. As such running all ddcutil commands until one is successful fixes the issue with my display. I did a very basic modification your code and it works. However I'm not experienced enough to implement this properly, so this issue.

If this would be implemented, something like --force option could be used with ddcci_plasmoid_backend to enable this functionality.

my code (only subprocess_wrapper and async_subprocess_wrapper require modification):

# Wrap sync and async subprocess calls for mocking
def subprocess_wrapper(cmd: str) -> CommandOutput:
    logger.debug('Execute command: `' + cmd + '`')
    proc = subprocess.run(cmd.split(' '), capture_output=True)
    stdout = proc.stdout.decode()
    while "DDC communication failed" in stdout:
        proc = subprocess.run(cmd.split(' '), capture_output=True)
        stdout = proc.stdout.decode()
        #print(stdout)
        stderr = proc.stderr.decode()
        command_output = {
            'returnCode': proc.returncode,
            'stdout': stdout,
            'stderr': stderr,
        }

    log_subprocess_output(cmd, command_output)
    if proc.returncode > 0:
        raise subprocess.CalledProcessError(returncode=proc.returncode, cmd=cmd, output=stdout, stderr=stderr)
    return command_output


async def async_subprocess_wrapper(cmd: str) -> CommandOutput:
    logger.debug('Execute command: `' + cmd + '`')
    proc = await asyncio.subprocess.create_subprocess_shell(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    # it's safe to assume that the return code is not None at this point
    return_code: int = 1 if proc.returncode is None else proc.returncode
    stdout, stderr = await proc.communicate()
    stdout = stdout.decode()
    while "DDC communication failed" in stdout:
        proc = await asyncio.subprocess.create_subprocess_shell(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        # it's safe to assume that the return code is not None at this point
        return_code: int = 1 if proc.returncode is None else proc.returncode
        stdout, stderr = await proc.communicate()
        stdout = stdout.decode()
        stderr = stderr.decode()
        command_output = {
            'returnCode': return_code,
            'stdout': stdout,
            'stderr': stderr,
        }

    log_subprocess_output(cmd, command_output)
    if proc.returncode > 0:
        raise subprocess.CalledProcessError(returncode=proc.returncode, cmd=cmd, output=stdout, stderr=stderr)
    return command_output

[davidhi7]

Will be part of the next major release