On 19/12/12 12:03, Éric Piel wrote:
The minimum period was set to 357 ns, while the divider for these boards is 50
ns. This prevented to output at maximum speed as ni_ao_cmdtest() would return
357 but would not accept it.
Not sure why it was set to 357 ns (this was done before the git history,
which starts 5 years ago). My guess is that it comes from reading the
specification stating a 2.8 MHz rate (~ 357 ns). The latest
specification states a 2.86 MHz rate (~ 350 ns), which makes a lot
more sense.
Tested on a pci-6251.
Signed-off-by: Éric Piel <piel@xxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <devel@xxxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Acked-By: Ian Abbott <abbotti@xxxxxxxxx>
Looks reasonable. The AO speed checks were added to the NI drivers (in
the out-of-tree Comedi sources before they were imported into "staging")
in early May 2007 but probably weren't tested to the limits.
(I'll make the same change to the out-of-tree Comedi sources on
www.comedi.org.)
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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