On 12/20/23 14:24, Csókás Bence wrote:
On 2023. 12. 20. 9:29, Dragan Simic wrote:
On 2023-12-20 08:52, Csókás Bence wrote:
On 2023. 12. 20. 8:09, Dragan Simic wrote:
On 2023-12-20 07:49, Csókás Bence wrote:
I don't think that would be a huge problem, Linux userspace can filter
ANSI control codes if it wants to. For now, I'd like a byte-for-byte
copy of the console, as-is, presented to Linux.
But wouldn't recording the control sequences as-is actually be pretty
much useless? For example, some user can spend a few minutes
scrolling through the boot menu, which would produce a fair amount of
nearly useless recorded data.
Moreover, if I'm not wrong, viewing or parsing such as-is data would
actually require replaying the control sequences, to reproduce the
actual console contents as it was recorded, which would be quite
cumbersome.
It *is* useless, but most of the times the user won't be scrolling at
all anyways, that's why I don't think these few extra bytes would be a
problem.
Quite frankly, when it comes to computing in general, taking the "ah, it
probably won't happen" approach isn't the best thing to do. We should
aim toward covering properly even the edge cases, if you agree.
You're absolutely right; however, I did not say "it won't happen", I
said that Linux userspace can go deal with it if it happens, and if it
wants to. And that in my opinion, the best course of action for U-Boot
is to record *everything* (as it does now), and then userspace can
decide to filter it for eg. ANSI codes. But I think it's best to keep
the U-Boot code dead simple, and also supply the most data to userspace.
That's what I read as well. Is there support for U-boot to write and
Linux to read PStores?
No and yes, but U-Boot can already read pstore. Please see
doc/usage/cmd/pstore.rst for the U-Boot part, and
Documentation/admin-guide/pstore-blk.rst for the Linux kernel part.
Irrelevant, as we only want to write out the console log to U-Boot, and
not the other way around (that's for collecting panic logs, which is
already implemented).
Another benefit of using pstore would be no permanently wasted RAM for
the recorded console contents. Also, having the data recorded to a
storage device also goes along with providing permanent records.
I'm positively *not gonna save boot logs to disk*, as most embedded
systems have Flash-based storage media; writing to them on every boot
would be devastating. Plus, I don't want the console subsystem to depend
on any file/disk operations/drivers.
pstore is agnostic to the backend used. In U-Boot we only support RAM
backends at the moment.
--Sean
