Hello Lukasz,
Am 16.05.2014 10:58, schrieb Lukasz Majewski:
Hi Wolfgang, Tom,
Hi Wolfgang,
Dear Lukasz,
In message<20140515090904.32f1d13d@amdc2363> you wrote:
What I complained about is the change in behaviour. I asked
to make the existing behaviour the default, so unaware users
will not be affected. Only if you intentionally want some
other behaviour you can then enable this by setting the env
variable.
Well, looking at mainline usage of DFU, Lukasz is speaking for
about half of the users / implementors. Since Denx is working
with the other half, can you shed some light on actual use vs
theoretical possibilities?
I don't want to urge anybody on making any conclusion here :-),
but I would be very grateful if we could come up with an
agreement.
As I've stated previously, my opinion is similar to the one
presented by Tom in this message.
For me it would be best to not calculate any checksum on default
and only enable it when needed.
I asked Heiko to run some actual tests on the boards where he has to
maintain DFU for. For a 288 MiB image he did not measure any
difference - with your patch applied, both with and without CRC
enabled, we would get the same (slow) 1:54 minutes download time.
As I've spoken with Heiko, am33xx uses NAND memory. I deal with eMMC.
Moreover, the size of "chunks" are different - 1 MiB and 32 MiB.
I must double check for the rationale for chunk size of 32 MiB at
Trats/Trats2 boards. I suspect, that eMMC write performance depend
on that.
I will perform some performance tests with 1 MiB chunk size and share
the result.
Unfortunately the 32 MiB is fixed for our platform. since lthor uses it
by default.
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.
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).
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).
Regarding L2 - our platform requires SMC calls to enable and manage L2
cache. In my opinion support for this in u-boot is an overkill.
Can we conclude this whole discussion? The main point was if we should
keep calculating and displaying crc32 as default for DFU transfers.
I'm for the option to NOT display and calculate it by default (PATCH
v3).
I talked with the siemens board customer, they also do not check/use
the displayed value from U-Boot ...
So, for me it is OK to not display this value ... but we should add
to DFU such a check ... or?
bye,
Heiko
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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