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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2021-07-15 18:01:21 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-21 09:11:19 +0200 |
| commit | 1bf2761c837571a66ec290fb66c90413821ffda2 (patch) | |
| tree | 36d1a8934d4f12c6734dd36e7dd3f0adacb89b84 /tools/perf/scripts/python/stackcollapse.py | |
| parent | 57560ee95cb7f91cf0bc31d4ae8276e0dcfe17aa (diff) | |
usb: hub: Fix link power management max exit latency (MEL) calculations
Maximum Exit Latency (MEL) value is used by host to know how much in
advance it needs to start waking up a U1/U2 suspended link in order to
service a periodic transfer in time.
Current MEL calculation only includes the time to wake up the path from
U1/U2 to U0. This is called tMEL1 in USB 3.1 section C 1.5.2
Total MEL = tMEL1 + tMEL2 +tMEL3 + tMEL4 which should additinally include:
- tMEL2 which is the time it takes for PING message to reach device
- tMEL3 time for device to process the PING and submit a PING_RESPONSE
- tMEL4 time for PING_RESPONSE to traverse back upstream to host.
Add the missing tMEL2, tMEL3 and tMEL4 to MEL calculation.
Cc: <stable@kernel.org> # v3.5
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210715150122.1995966-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools/perf/scripts/python/stackcollapse.py')
0 files changed, 0 insertions, 0 deletions