Messages in this thread | | | Date | Fri, 28 Aug 2020 12:57:42 +0530 | From | Vinod Koul <> | Subject | Re: [PATCH 05/11] soundwire: bus: update multi-link definition with hw sync details |
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On 26-08-20, 09:09, Pierre-Louis Bossart wrote: > > > > > + * @hw_sync_min_links: Number of links used by a stream above which > > > + * hardware-based synchronization is required. This value is only > > > + * meaningful if multi_link is set. If set to 1, hardware-based > > > + * synchronization will be used even if a stream only uses a single > > > + * SoundWire segment. > > > > Soundwire spec does not say anything about multi-link so this is left to > > implementer. Assuming that value of 1 would mean hw based sync will > > be used even for single stream does not make sense in generic terms. > > Maybe yes for Intel but may not be true for everyone? > > hw-based sync is required for Intel even for single stream. It's been part > of the recommended programming flows since the beginning but ignored so far. > > That said, this value is set by each master implementation, no one forces > non-Intel users to implement an Intel-specific requirement. > > > We already use m_rt_count in code for this, so the question is why is > > that not sufficient? > > Because as you rightly said above, Intel requires the hw_sync to be used > even for single stream, but we didn't want others to be forced to use the > hw-sync for single stream. the m_rt_count is not sufficient for Intel. > > I think we are in agreement on not forcing everyone to follow what is > required by Intel, and that's precisely why we added this setting. If you > set it to two you would only use hw_sync when two masters are used.
Okay, it would be better if we move it to intel driver, but I see it may not be trivial, so lets go with this approach.
-- ~Vinod
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