Hi Simon,


On 4/19/23 03:49, Simon Glass wrote:
Hi Filip,

On Tue, 11 Apr 2023 at 14:24, Filip Žaludek <filip.zalu...@oracle.com> wrote:



On 2/8/23 20:01, Mark Kettenis wrote:
Date: Wed, 8 Feb 2023 19:45:36 +0100
From: Michal Suchánek <msucha...@suse.de>

Hello,

On Wed, Jan 18, 2023 at 05:01:12PM +0100, Filip Žaludek wrote:


Hi Michal,

   thanks for testing! Do you consider keyboard as working once it is detected 
without
'usb_kbd usb_kbd: Timeout poll on interrupt endpoint', or judging from 
subsequent
typing? Note that issue is reproducible only in about 20% of reboots.

I rely on keyboard input to boot so if it was 20% broken I would notice.
I don't use the rPi all that much so if it was broken only a few
% of the time there is a chance I would miss it.

However, for me not typing on the keyboard during usb detection it is
100% not detected, typing on it during usb detection it is 100%
detected.

The timeout is limitation of the dwc2 controller handling of usb hubs.

There might be a possibility to improve the driver so that it handles
the condition but it might be that the Linux driver relies on a separate
thread handling the controller which is not acceptable for u-boot.

I am not usb expert and definitely not dwc2 expert so I cannot do more
than workaround the current driver limitation.

For me I can always enter 'U-Boot>' shell, but then keyboard usually does not 
work.
And yes, resetting the usb controller with pressing a key afterwards will
finally break the keyboard. ('usb reset' typed from keyboard)
If you are Prague located I am ready to demonstrate what I am talking about.

   Simon's keyboard detection is somewhat interfered by 'SanDisk USB Extreme 
Pro' detection,
printed complaints but keyboard still works..
'usb_kbd usb_kbd: Timeout poll on interrupt endpoint' and 'Failed to get 
keyboard state from device 0c40:8000'
Btw. why from 0c40:8000 (ELMCU 2.4GHz receiver) when wired keyboard is 
046d:c31c (Logitech Keyboard K120)?

   What is supposed scenario for RPi3/u-boot/grub usb keyboard equipped users 
wanting to boot non-default?
Enter 'U-Boot>' shell to detect keyboard; type boot; select desired grub 
entry..?

Reverting either from the two makes it non issue for me:
'dwc2: use the nonblock argument in submit_int_msg'
commit 9dcab2c4d2cb50ab1864c818b82a72393c160236

Without this booting from USB is not feasible because reading every
block from the USB drive waits for the keyboard to time out.

'console: usb: kbd: Limit poll frequency to improve performance'
commit 96991e652f541323a03c5b7e075d54a117091618

No idea about this one, for me it doea not give any substantial
difference in behavior.

Reverting that commit leads to a significant slowdown loading a kernel
from disk with a usb keyboard connected.  The slowdown is somewhat
hardware dependent but on some systems loading the OpenBSD/arm64
kernel would take minutes instead of seconds.


Hello,
    I am about to dig more into this issue with proper tools, but failed to
configure/compile trace functionality on RPi3 due to missing references
to timer_early_get_count() and timer_early_get_rate().

You could implement a proper timer driver for rpi.


   Is it possible/feasible to implement calls in CONFIG_SYS_ARCH_TIMER
and/or CONFIG_SP804_TIMER?

Yes


 I am little bit missing here secret sauce, timer_early_get_count() and 
timer_early_get_rate()
are not supposed to be implemented in arch/arm/cpu/armv8/generic_timer.c? But 
predestined for
drivers/timer/sp804_timer.c?

TIMER is required for common/board_f.c and common/board_r.c but it disables 
generic_timer..
%< -----------------------------------------
ifndef CONFIG_$(SPL_TPL_)TIMER
obj-$(CONFIG_SYS_ARCH_TIMER) += generic_timer.o
endif
%< -----------------------------------------
And obviously multiple definition of get_tbclk and get_ticks when forced to 
compile/link.





   I would be grateful even for trace to generate function traces without
timestamps. Is such nasty hack without timestamping supposed to work?
Basically my intention is to trace 'usb reset'.

Appreciate any hints/outlines how to proceed.

I assume you mean CONFIG_TRACE. Yes, you could update it to support
writing a zero timestamp. See the add_ftrace() function.

But better to add a driver if you can. It should not be difficult.

Regards,
Simon

 I am already happily timestamp tracing with borrowed functionality from 
generic_timer.c,
albeit bypassing kbuild mechanism. It did not yet answered my usb polling 
questions,
tracing report is polluted/overfilled.



Instrumenting code thoughts:
* It would be handy to -finstrument-functions only for desired objects.
* It would be handy to have macro inverse to 'notrace' to mark only desired 
functions. Feasible?
* gcc -finstrument-functions-exclude-file-list still pollutes tracing buffer.

More Tracing in U-Boot thoughts:
* There is proftool options discrepancy, documented {-c, -f, -m, -o, -t, -v}, 
implemented {-m, -p, -t, -v}.
* Both types FUNCF_ENTRY and FUNCF_EXIT are marked as " <- " by proftool.



Thanks,
Filip

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