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SubjectRe: [alsa-devel] [PATCH 0/3] soundwire: use UniqueID only when relevant
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On 10/22/19 6:48 PM, Pierre-Louis Bossart wrote:
> The hardware UniqueID, typically enabled with pin-strapping, is
> required during enumeration to avoid conflicts between devices of the
> same type.
>
> When there are no devices of the same type, using the UniqueID is
> overkill and results in a lot of probe errors due to mismatches
> between ACPI tables and hardware capabilities. For example it's not
> uncommon for BIOS vendors to copy/paste the same settings between
> platforms but the hardware pin-strapping is different. This is
> perfectly legit and permitted by MIPI specs.
>
> With this patchset, the UniqueID is only used when multiple devices of
> the same type are detected. The loop to detect multiple identical
> devices is not super efficient but with typically fewer than 4 devices
> per link there's no real incentive to be smarter.
>
> This change is only implemented for ACPI platforms, for DeviceTree
> there is no change.

Vinod, this series has been submitted for review on October 22 and I
answered to your questions. There's been no feedback since October 24,
so is there any sustained objection here?

ACPI platforms are completely unmanageable without this patchset.

>
> Pierre-Louis Bossart (3):
> soundwire: remove bitfield for unique_id, use u8
> soundwire: slave: add helper to extract slave ID
> soundwire: ignore uniqueID when irrelevant
>
> drivers/soundwire/bus.c | 7 +--
> drivers/soundwire/slave.c | 98 +++++++++++++++++++++++++++--------
> include/linux/soundwire/sdw.h | 4 +-
> 3 files changed, 84 insertions(+), 25 deletions(-)
>

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