[PATCH 11/14] cxl: Workaround PE=0 hardware limitation in Mellanox CX4

[Frederic Barrat]

Le 04/07/2016 15:22, Ian Munsie a écrit :
> From: Ian Munsie <imunsie at au1.ibm.com>
>
> The CX4 card cannot cope with a context with PE=0 due to a hardware
> limitation, resulting in:
>
> [   34.166577] command failed, status limits exceeded(0x8), syndrome 0x5a7939
> [   34.166580] mlx5_core 0000:01:00.1: Failed allocating uar, aborting
>
> Since the kernel API allocates a default context very early during
> device init that will almost certainly get Process Element ID 0 there is
> no easy way for us to extend the API to allow the Mellanox to inform us
> of this limitation ahead of time.
>
> Instead, work around the issue by extending the XSL structure to include
> a minimum PE to allocate. Although the bug is not in the XSL, it is the
> easiest place to work around this limitation given that the CX4 is
> currently the only card that uses an XSL.
>
> Signed-off-by: Ian Munsie <imunsie at au1.ibm.com>

Reviewed-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>