issues.txt

ISSUES

Known issues of Circle are:

* There are known issues with the included USB library (e.g. no error recovery,
  limited split support, no isochronous support). You should only attach the USB
  devices, which are needed for your application!

* Circle is not a real-time OS. That means different simultaneous operations may
  interfere in respect of its timing behaviour. The provided samples are tested to
  work but if you try different combinations of hardware support classes this has
  to be tested by yourself. Nevertheless real-time applications based on Circle
  are possible. Have a look at doc/realtime.txt for more information!

* According to tests with the current firmware, 4K display resolutions on a
  Raspberry Pi 4 with Circle are only possible, if the option "hdmi_enable_4kp60=1"
  is enabled in the file config.txt and are not possible with the cut-down firmware
  (start_cd.elf). This may change with future firmware versions.

* sample/31-webclient does not work any more, because of the missing SSL/TLS
  support. SSL/TLS support for Circle is developed here:

	https://github.com/smuehlst/circle-stdlib

* Some modules in the addon/ subdirectory will not build with STDLIB_SUPPORT = 0.

* The class CHDMISoundBaseDevice will not link with STDLIB_SUPPORT = 0
  and AARCH = 32.

* There may be a few USB devices, which report a transfer error 3 (babble) on the
  Raspberry Pi 4. According to some comments on the Internet, this may be caused
  by incompatibilities of the USB device firmware. These devices cannot be used
  with Circle on the Raspberry Pi 4 currently.


You can see or report further issues here:

	https://github.com/rsta2/circle/issues