Network functionality in v2020.04 on Raspberry Pi 4

[Jevtic, Sasha]

[Previous message to list canceled; resending with added detail]

Harald,

To be clear, the language I used was to imply *only* that I observed this problem as recently as the latest release; none over the earlier builds I have prepared for RPi4 worked better.  The reference to other hardware and older U-Boot was simply intended to suggest that the network infrastructure, notably including the DHCP and TFTP servers, have been proven to work with U-Boot.

Moreover, I would like to point out that I am chain loading U-Boot from the RPi4 firmware via TFTP.  This could be a significant point since the RPi4 firmware will have clearly already have initialized the Ethernet hardware previously.

Thanks.

Sasha

-----Original Message-----
From: Harald Seiler <hws at denx.de> 
Sent: Friday, April 17, 2020 4:12 AM
To: Jevtic, Sasha <sasha.jevtic at continental-corporation.com>; u-boot at lists.denx.de
Cc: Matthias Brugger <mbrugger at suse.com>
Subject: Re: Network functionality in v2020.04 on Raspberry Pi 4

Hello Sasha,

adding Matthias Brugger on Cc as he is the maintainer for Raspberry Pi.

On Thu, 2020-04-16 at 20:25 +0000, Jevtic, Sasha wrote:
> Hello all,
> 
> I am encountering considerable difficulty with the networking 
> functionality on Raspberry Pi 4 on the latest release (2020.04).  In 
> particular, I have observed:
> 
>     * any network operation that fails renders networking functionality
>       inoperable until reboot.
>     * ping always fails.
>     * TFTP download attempt of non-existent file fails (resulting in
>       subsequent network operations failing).
>     * TFTP download of an existing file usually works, but occasionally
>       experiences timeouts during transfers; some are timeouts are
>       intermittent (the transfer ultimately resumes), and some are
>       permanent.
>     * TFTP download of a script usually works (as above). The script
>       will run, but any additional TFTP downloads performed by a script
>       all fail.
> 
> It is not entirely clear right now whether this is a problem in U-Boot 
> (i.e., instead of in the execution environment set up by the Raspberry 
> Pi firmware), but the TFTP infrastructure I am using is known to work 
> well with other hardware running an older version of U-Boot.  Also, 
> there are also no network issues in the Linux environment that I 
> ultimately boot, so hardware also seems unlikely.  Thus, suggestions 
> for things to check would be appreciated; I am of course also happy to 
> provide any supporting data required to investigate.

If you have know which older version still worked, you can use git-bisect [1] to find out where the regression was introduced.  Ideally, if you can automate installation of a newly built U-Boot version, this can run entirely unattended to find out where the bug was introduced.

[1]: https://git-scm.com/docs/git-bisect

> Please also be aware that I initially posted a very similar inquiry to 
> the Raspberry Pi Forum:
> 
> https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=271068
> 
> Thanks.
> 
> Sasha
--
Harald