[PATCH rtems-libbsd 1/2] if_ffec: Reduce buffer size

[Gedare Bloom]

On Thu, Jun 2, 2022 at 2:28 AM Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> On 02/06/2022 09:27, Christian MAUDERER wrote:
> >
> > Am 01.06.22 um 14:46 schrieb Gedare Bloom:
> >> On Mon, May 23, 2022 at 6:21 AM Christian Mauderer
> >> <christian.mauderer at embedded-brains.de> wrote:
> >>>
> >>> Typical embedded systems don't have that much memory. Reduce the buffer
> >>> size to something more sensible for the usual type of application.
> >>> ---
> >>>   freebsd/sys/dev/ffec/if_ffec.c | 8 ++++++++
> >>>   1 file changed, 8 insertions(+)
> >>>
> >>> diff --git a/freebsd/sys/dev/ffec/if_ffec.c
> >>> b/freebsd/sys/dev/ffec/if_ffec.c
> >>> index 47c0f770..4c1e147b 100644
> >>> --- a/freebsd/sys/dev/ffec/if_ffec.c
> >>> +++ b/freebsd/sys/dev/ffec/if_ffec.c
> >>> @@ -139,9 +139,17 @@ static struct ofw_compat_data compat_data[] = {
> >>>   /*
> >>>    * Driver data and defines.  The descriptor counts must be a power
> >>> of two.
> >>>    */
> >>> +#ifndef __rtems__
> >>>   #define        RX_DESC_COUNT   512
> >>> +#else /* __rtems__ */
> >>> +#define        RX_DESC_COUNT   64
> >>> +#endif /* __rtems__ */
> >>
> >> Do we need some way to control this parameter? Or, how will this
> >> appear if it breaks something?
> >
> > I don't expect that there will be any problems. But I can take a look
> > how I can make that a parameter.
>
> Can we please keep this a compile time constant as it is.  The 64
> descriptors should be more than enough.
>
I don't mind the reduction of the constant, but it would be good to
predict what behavior might indicate this was exceeded. I guess it
should be some kind of errno on an allocation request though? So it
should be fine, but if a user hits this limit, I guess they have
pretty limited options to overcome it.

> --
> embedded brains GmbH
> Herr Sebastian HUBER
> Dornierstr. 4
> 82178 Puchheim
> Germany
> email: sebastian.huber at embedded-brains.de
> phone: +49-89-18 94 741 - 16
> fax:   +49-89-18 94 741 - 08
>
> Registergericht: Amtsgericht München
> Registernummer: HRB 157899
> Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
> Unsere Datenschutzerklärung finden Sie hier:
> https://embedded-brains.de/datenschutzerklaerung/