Re: [RFC] QR encoding for Oops messages

[Teodora Băluţă]

On Wed, Mar 19, 2014 at 10:28 PM, Levente Kurusa <levex@xxxxxxxxx> wrote:
> Hi,
>
> 2014-03-19 21:18 GMT+01:00 Dave Jones <davej@xxxxxxxxxx>:
>> On Mon, Mar 17, 2014 at 02:59:47PM -0700, Teodora Baluta wrote:
>>  > This feature encodes Oops messages into a QR barcode that is scannable by
>>  > any device with a camera.
>>
>>  ...
>>
>>  >  include/linux/print_oops.h |   11 +
>>  >  include/linux/qrencode.h   |  546 +++++++++++++
>>  >  kernel/Makefile            |    1 +
>>  >  kernel/panic.c             |    5 +
>>  >  kernel/print_oops.c        |  173 +++++
>>  >  kernel/printk/printk.c     |    9 +-
>>  >  lib/Kconfig                |    5 +
>>  >  lib/Kconfig.debug          |   11 +
>>  >  lib/Makefile               |    3 +
>>  >  lib/qr/Makefile            |    6 +
>>  >  lib/qr/bitstream.c         |  233 ++++++
>>  >  lib/qr/bitstream.h         |   37 +
>>  >  lib/qr/mask.c              |  320 ++++++++
>>  >  lib/qr/mask.h              |   39 +
>>  >  lib/qr/mmask.c             |  175 +++++
>>  >  lib/qr/mmask.h             |   36 +
>>  >  lib/qr/mqrspec.c           |  259 +++++++
>>  >  lib/qr/mqrspec.h           |  155 ++++
>>  >  lib/qr/qrencode.c          |  871 +++++++++++++++++++++
>>  >  lib/qr/qrencode.h          |  546 +++++++++++++
>>  >  lib/qr/qrinput.c           | 1834 ++++++++++++++++++++++++++++++++++++++++++++
>>  >  lib/qr/qrinput.h           |  129 ++++
>>  >  lib/qr/qrspec.c            |  543 +++++++++++++
>>  >  lib/qr/qrspec.h            |  178 +++++
>>  >  lib/qr/rscode.c            |  325 ++++++++
>>  >  lib/qr/rscode.h            |   38 +
>>  >  lib/qr/split.c             |  331 ++++++++
>>  >  lib/qr/split.h             |   44 ++
>>  >  28 files changed, 6860 insertions(+), 3 deletions(-)
>
> This idea is certainly great.
>
> However, there are quite a few problems with the code in terms of code style and
> other terms as well. I am not sure how could we help you make this code
> appliable, but it would be great if you put up a branch somewhere. This way
> I could send you a few commits that do some fixups.

Wow, that'd be great! I have set up my clone of the kernel source up
on gitlab [0] and github [1]. I will update the remote branch asap (I
made some coding style fixups that aren't present on github/gitlab
right now, only in a remote branch). Is this ok?

>
>>
>> That's a ton of code we're adding into one of the most fragile parts of the kernel.
>
> Indeed, this should get split up.
>
>>
>> A lot of what libqrencode does would seem to be superfluous to the requirements
>> here, as we don't output kernel oopses in kanji for eg, and won't care about
>> multiple versions of the qr spec.
>>
>> How much of this could we drop ?
>
> A lot, most likely.

Indeed.

>
> Also, I wonder if we could do the same for panic()?
> I hate it when I receive a panic and I have no idea what's the cause
> since my display is filled up with the stack trace.

Most likely panic is harder to do for reasons discussed in this thread here [2].


[0] https://gitlab.com/teobaluta/opw
[1] https://github.com/teobaluta/qr-linux-kernel
[2] https://lwn.net/Articles/503677/

Thanks,
Teodora
>
> --
> Regards,
> Levente Kurusa
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