Re: Serial issues with EG20T (Topcliff) PCH uarts

[Darren Hart <dvhart@linux.intel.com>]

Hi Alan,

Thanks for the suggestions. Still not working, details follow.

On 09/27/2011 02:57 PM, Alan Cox wrote:
>> Using the ti_usb_3410_5052 driver with modified vendor/product strings, I am
>> able to get ttyUSB0 on my host and open it in minicom:
>>
>> $ sudo modprobe ti_usb_3410_5052 vendor_3410=0x0451 product_3410=0x5053
>> $ minicom -D /dev/ttyUSB0
> 
> Please submit those idents to GregKH for the ti_usb driver.
> 

I will. I need to confirm this is something I can do now (if I can use
the product name, etc.).

>> Can anyone offer up some ideas on what I might try to get:
>>
>> 1) the getty working
>> 2) the earlier kernel messages to appear
>> 3) syslinux working
>>
>> over the serial port?
> 
> It may depend a lot on the port. If it boots in PCI D3 (power saved) then
> it's going to be fun. Otherwise forcing the address of the port ought to
> do the trick.
> 
> See	
> 	console=uart8250,io 0xb060,115200n8

I tried:

console=uart8250,io,0xb060,115200n8

With this I got 4 non-ascii chars

> 
> although it's polled so you may want to drop the speed a bit!

I switched all my terminal emulators, syslinux config, the getty, and
console redirection in the bios to use 9600n8. Then ran with:

console=uart8250,io,0xb060,9600n8

This printed several bursts of garbled non-ascii strings, but did so
very early! :)

With minicom on each end, I see the INT 18 count go up by 1 for every
char sent from the board and up by 3 for every char sent from my dev
box, as well as the irregular rx,fe increment mentioned originally.

> 
> netconsole might also be useful to debug the early serial problems !

I did give that a shot, it complained about eth0 not existing, despite
the driver being compiled in. Possibly an init race with netconsole and
pch_gbe? Similar posts sent to linux-next earlier this year.


> 
> No idea for syslinux.

Doesn't like 9600 either.

> 
> Alan

So I'm bugging the hardware/firmware guys, really looks like something
is bad under the covers to me.

Thanks Alan!

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel