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SubjectRe: I need advice with UPS connection. (ping)
On Mon, 15 Nov 2021 11:09:18 -0500
stern@rowland.harvard.edu wrote:
<snip>
> You can test the theory by patching the kernel, if you want. The code
> to change is in the source file drivers/hid/usbhid/hid-core.c, and the
> function in question is hid_set_idle() located around line 659 in the
> file. Just change the statement:
>
> return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
> HID_REQ_SET_IDLE, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> (idle << 8) | report, ifnum, NULL, 0, USB_CTRL_SET_TIMEOUT);
>
> to:
>
> return 0;
>
> to prevent the Set-Idle request from being sent. If the device still
> insists on disconnecting then we'll know that this wasn't the reason.
>

Ok, so I changed out the line above with "__panic(2);" and now my PC just
reboots.... Teasing :D
That didn't seem to change anything. I'll attach another dump just in
case it reveals more.

> Also, if you have another system (say, one running Windows) which the
> UPS does work properly with, you could try collecting the equivalent of
> a usbmon trace from that system for purposes of comparison. (On
> Windows, I believe you can use Wireshark to trace USB communications.)
>

Limitations of SW:
Wireshark works if you have windows in a virtual environment, but I don't
actually own... I mean license, any windowz products. I'm a straight
Luser.
So borrowed a windowz machine and plugged in the UPS. I then used USBPcap
to capture the data after installing the drivers. It has 4 things it can't
detect:

Bus states (Suspended, Power ON, Power OFF, Reset, High Speed Detection
Handshake)
Packet ID (PID)
Split transactions (CSPLIT, SSPLIT)
Duration of bus state and time used to transfer packet over the wire
Transfer speed (Low Speed, Full Speed, High Speed)

I'm 100% certain the last 2 we don't care about. IDK about the others.




Notes:
Here's the product page of my UPS.
https://www.newegg.com/opti-ups-ts2250b/p/N82E16842107014
The main webpage for USBPcap is here:
https://desowin.org/usbpcap/index.html
I can also try and use SnoopyPro and busdog if the output is undesirable.
USBPcap spits out a pcap file which can be analyzed by wireshark
using dissectors -- somehow (I really should practice using wireshark.)



Test and capture procedure:
When I installed the drivers it asked me where to look for the UPS. I
didn't tell it the USB port until after I started USBPcap and then
plugged in the UPS. Then the GUI opened up and I could see a lot of cool
controls like the battery power, loading, etc. The loading was 132W and
the battery was at 100%. Then I ran a self test (There's a button in the
GUI) and it worked fine. Then I unplugged the UPS and it crashed. Then I
plugged it back in. All --100%-- of this is in the pcap file.

Results of:
After unplugging the UPS it's battery dropped to 22% and then it turned
off. My UPS is 2y and 5m old. It has a 3Y parts warranty. I guess I'll
see if they'll honor it.




I'm still interested in talking to it via my Linux PC, of course.

Thanks,
David
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