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Bug #10344

xhci port capabilities warning is confusing

Added by Robert Mustacchi 10 months ago. Updated 10 months ago.

Status:
Closed
Priority:
Normal
Category:
driver - device drivers
Start date:
2019-02-05
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:

Description

Today we parse the xhci port capabilities section to try and find what exists. When we encounter a port version that we don't understand, we issue a warning. This ends up looking like:

WARNING: xhci0: encountered port capabilities with unknown major USB version: 51382274

This warning is confusing for two reasons. One is that that number makes no sense. This is raw value of the port configuration register. We should just use the major and minor version. Secondly, this is confusing because it's not actually a major version specifically.

The fix will be to have it look like %x.%x which would become 3.10.

History

#1

Updated by Robert Mustacchi 10 months ago

To test this, I manually stepped through xhci_port_count. When we read the version from the register, I edited it in mdb as follows:

xhci`xhci_port_count+0x9b:      call   -0x1030  <xhci`xhci_get32>
[0]> ::step over
kmdb: target stopped at:
xhci`xhci_port_count+0xa0:      movl   -0x44(%rbp),%edx
[0]> <rax=K
                2000802         
[0]> 23230802>rax

With that in place, we eventually saw:

WARNING: xhci0: encountered port capabilities with unknown USB version: 23.23

Which makes a lot more sense and is useful to folks.

#2

Updated by Electric Monk 10 months ago

  • Status changed from New to Closed

git commit c78b1a4529122c8f26c5b25b88f01dc4800751a0

commit  c78b1a4529122c8f26c5b25b88f01dc4800751a0
Author: Robert Mustacchi <rm@joyent.com>
Date:   2019-02-12T22:14:57.000Z

    10344 xhci port capabilities warning is confusing
    Reviewed by: Jason King <jason.king@joyent.com>
    Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
    Reviewed by: Mike Zeller <mike.zeller@joyent.com>
    Reviewed by: Toomas Soome <tsoome@me.com>
    Reviewed by: Gergő Mihály Doma <domag02@gmail.com>
    Approved by: Dan McDonald <danmcd@joyent.com>

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