Hi Wolfgang,
Dear Lukasz,
In message 20140515154334.626923b4@amdc2363 you wrote:
This reinforces my speculation that you are actually addressing the wrong problem. Instead of adding new code and environment variables and making the system even more complex, we should just leave everything as is,
During working on this patch I've replaced the crc32() method with the call to hash_method(), which IMHO is welcome.
Yes, indeed this is highly welcome. Thanks a lot for that!
I also don't personally like the crc32, hence I like the choice which this patch gives me to use other algorithm (for which I've got HW support on my platform - e.g. MD5).
Well, is this really useful? dfu-utils provides only CRC caculation, so where would you get the reference value for any other checksum metod from?
I was rather thinking about a test setup with my target connected via serial console to HOST machine. Then I could compare the CRC32/MD5/SHA1 just after sending the data.
For my target it is better to use MD5 or SHA1 since support for them is provided via the specialized, embedded crypto IP.
and you should try to find out why the CRC calculation is so low for you. Checking if caches are enabled is probably among the things that should be done first.
L1 is enabled. L2 has been disabled on purpose (power consumption reduction).
This certainly contributes to slow code execution.
Please note that the last revision of DFU is from 2004. I've contacted Greg KH (one of the original authors) and he replied that no new attempt to revise the standard was made.
This may just mean that users were just happy with the current situation.
It is hard to say.
It's definitely better than if changed had been proposed but rejected.
True.
The best however, would be to revise the standard to include such functionality to it. In the same time I'm fully aware that this is very unlikely to happen.
Why do you think it is unlikely?
I don't have the experience with preparing USB standards, but I assume that it is somewhat hard to revise the standard after 10 years.
Of course, it would require that someone comes up with such a proposal in the first place. But you sound as if you were certain a proposal had no chance for being considered.
No, this is not what I meant.
I may be naive, but should we not at least try before giving up?
Unfortunately my time budget is limited and I feel like this has lower priority than fixing/solving current DFU problems.
Best regards,
Wolfgang Denk