USB and EOL LTS Kernel Advice

USB and EOL LTS Kernel Advice

[Jate Sujjavanich]

I have a device running the 4.19 LTS kernel which just went end of
life. It has some USB signal integrity issues which result in "clear
tt" loops until the bus can recover (if it can). This can result in
system hangs including with lsusb.

Management would like for me to patch our Linux kernel to work around
the problem thinking that a kernel fix is much less costly than
deploying a hardware fix. There are some USB fixes in the upstream
which might help. But I think I will be without community support.

What advice do you have?


- Jate S.

Re: USB and EOL LTS Kernel Advice

[Greg KH]

On Tue, Dec 31, 2024 at 09:59:45AM -0500, Jate Sujjavanich wrote:
> I have a device running the 4.19 LTS kernel which just went end of
> life. It has some USB signal integrity issues which result in "clear
> tt" loops until the bus can recover (if it can). This can result in
> system hangs including with lsusb.
> 
> Management would like for me to patch our Linux kernel to work around
> the problem thinking that a kernel fix is much less costly than
> deploying a hardware fix. There are some USB fixes in the upstream
> which might help. But I think I will be without community support.
> 
> What advice do you have?

Upgrade to a newer, and properly supported, kernel version.  4.19 is
already very old and obsolete and full of known security problems.  If
you stick to 4.19, you are on your own for all support and everything
else.

Good luck!

greg k-h

Re: USB and EOL LTS Kernel Advice

[Greg KH]

On Wed, Jan 01, 2025 at 11:18:51AM +0100, Greg KH wrote:
> On Tue, Dec 31, 2024 at 09:59:45AM -0500, Jate Sujjavanich wrote:
> > I have a device running the 4.19 LTS kernel which just went end of
> > life. It has some USB signal integrity issues which result in "clear
> > tt" loops until the bus can recover (if it can). This can result in
> > system hangs including with lsusb.

Also, this really sounds like a hardware issue, right?  Why do you think
this is a software issue?  For USB, there's only so much the kernel can
do when you have bad signals or electrical connections.

Try running a more modern kernel and see if that helps, otherwise, I
recommend fixing the hardware issues first :)

thanks,

greg k-h