On 02/15/2013 02:37 PM, Johannes Berg wrote:
On Fri, 2013-02-15 at 14:31 +0100, Marco Porsch wrote:
Hi,
On 02/15/2013 01:46 PM, Johannes Berg wrote:
On Fri, 2013-02-15 at 12:40 +0000, marco@xxxxxxxxxxx wrote:
Please check again. The comment is split in two and placed on the respective new positions.
Yeah, I see, the API is just total shit. First passing the TSF and then
calculating it to override? Why not do the calculation outside the API
always?
The TBTT calculation does intentionally not use the mactime value.
Synchronization uses the time in local TSF units and the exact same time
point in peers TSF units at the time of sending/receiving (mactime field).
The TBTT calculation uses the time of NOW, i.e. the current TSF after
possible delays in firmware/driver/rx-handler which may have outdated
the mactime field.
I'm talking about this API:
mesh_neighbour_update:
...
tsf = drv_get_tsf()
...
sync_ops->rx_bcn(..., tsf)
mesh_sync_offset_rx_bcn(..., t_r):
...
if (have_better_timestamp)
t_r = get_better_timestamp()
You can hardly claim that's an intuitive API.
Hm, alright. Just saying that ieee80211_mps_sta_tbtt_update still uses
the unchanged TSF value. But hey :)
What would be more favourable then?
a) second variable in mesh_sync_offset_rx_bcn
mesh_neighbour_update:
...
tsf = drv_get_tsf()
...
sync_ops->rx_bcn(..., tsf)
ieee80211_mps_sta_tbtt_update(..., tsf);
mesh_sync_offset_rx_bcn(..., tsf):
...
if (have_better_timestamp)
t_r = get_better_timestamp()
else
t_r = tsf;
b) second variable in mesh_neighbour_update
mesh_neighbour_update:
...
tsf = drv_get_tsf()
if (have_better_timestamp)
t_r = get_better_timestamp()
else
t_r = tsf;
...
sync_ops->rx_bcn(..., t_r)
ieee80211_mps_sta_tbtt_update(..., tsf);
--Marco
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