ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Tests: USB: Add a README for Linux users 

Explain how to overcome xHCI limitations in kernels prior to v4.17 and
successfully run USB tests.
pull/9768/head
Filip Jagodzinski 2018-12-14 17:41:19 +01:00 committed by Russ Butler
parent 7354eb2779
commit 1ec448dbd0
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
TESTS/usb_device/basic/README.md Normal file
View File

@ -0,0 +1,15 @@
# Testing the USB device data toggle reset with a Linux host
When you run the `tests-usb_device-basic` test suite on a Linux machine, please make
sure that at least one of the following prerequisites are met:
* using the Linux kernel ***4.17* or newer**,
* using the ***eHCI*** USB driver instead of *xHCI*.
Implementations of the *xHCI* driver prior to version 4.17 of the Linux kernel did
not have the functionality necessary to test `"endpoint test data toggle reset"`.
Even though the data toggle is correctly reset on the device side, the host side will
not be synchronized and the test will falsely fail.
Further reading:
1. [the Linux kernel patch adding missing xHCI behavior](https://github.com/torvalds/linux/commit/f5249461b504d35aa1a40140983b7ec415807d9e),
1. [LKML discussion explaining the details of this issue](https://lkml.org/lkml/2016/12/15/388).