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From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: alsa-devel@alsa-project.org
Cc: tiwai@suse.de, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
	vkoul@kernel.org, broonie@kernel.org,
	srinivas.kandagatla@linaro.org, jank@cadence.com,
	slawomir.blauciak@intel.com,
	Bard liao <yung-chuan.liao@linux.intel.com>,
	Rander Wang <rander.wang@linux.intel.com>
Subject: Re: [alsa-devel] [PATCH 0/3] soundwire: use UniqueID only when relevant
Date: Wed, 6 Nov 2019 13:30:27 -0600	[thread overview]
Message-ID: <caa9b0cb-ea85-e7de-6ada-35ad906dec28@linux.intel.com> (raw)
In-Reply-To: <20191022234808.17432-1-pierre-louis.bossart@linux.intel.com>



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(-)
> 

WARNING: multiple messages have this Message-ID
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: alsa-devel@alsa-project.org
Cc: tiwai@suse.de, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
	vkoul@kernel.org, broonie@kernel.org,
	srinivas.kandagatla@linaro.org, jank@cadence.com,
	slawomir.blauciak@intel.com,
	Bard liao <yung-chuan.liao@linux.intel.com>,
	Rander Wang <rander.wang@linux.intel.com>
Subject: Re: [alsa-devel] [PATCH 0/3] soundwire: use UniqueID only when relevant
Date: Wed, 6 Nov 2019 13:30:27 -0600	[thread overview]
Message-ID: <caa9b0cb-ea85-e7de-6ada-35ad906dec28@linux.intel.com> (raw)
In-Reply-To: <20191022234808.17432-1-pierre-louis.bossart@linux.intel.com>



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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  parent reply	other threads:[~2019-11-06 19:30 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-22 23:48 [PATCH 0/3] soundwire: use UniqueID only when relevant Pierre-Louis Bossart
2019-10-22 23:48 ` [alsa-devel] " Pierre-Louis Bossart
2019-10-22 23:48 ` [PATCH 1/3] soundwire: remove bitfield for unique_id, use u8 Pierre-Louis Bossart
2019-10-22 23:48   ` [alsa-devel] " Pierre-Louis Bossart
2019-10-24 11:29   ` Vinod Koul
2019-10-24 11:29     ` [alsa-devel] " Vinod Koul
2019-10-24 12:42     ` Pierre-Louis Bossart
2019-10-24 12:42       ` Pierre-Louis Bossart
2019-10-22 23:48 ` [PATCH 2/3] soundwire: slave: add helper to extract slave ID Pierre-Louis Bossart
2019-10-22 23:48   ` [alsa-devel] " Pierre-Louis Bossart
2019-10-22 23:48 ` [PATCH 3/3] soundwire: ignore uniqueID when irrelevant Pierre-Louis Bossart
2019-10-22 23:48   ` [alsa-devel] " Pierre-Louis Bossart
2019-10-24 11:39   ` Vinod Koul
2019-10-24 11:39     ` [alsa-devel] " Vinod Koul
2019-10-24 12:59     ` Pierre-Louis Bossart
2019-10-24 12:59       ` Pierre-Louis Bossart
2019-11-06 19:30 ` Pierre-Louis Bossart [this message]
2019-11-06 19:30   ` [alsa-devel] [PATCH 0/3] soundwire: use UniqueID only when relevant Pierre-Louis Bossart
2019-11-09 11:18 ` Vinod Koul
2019-11-09 11:18   ` [alsa-devel] " Vinod Koul

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