linux-kernel - Re: [PATCH v2] ACPI: bus: Use OF match data for PRP0001 matched devices

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Message-ID: <abfdb44d-108a-49d5-98ad-949d184f4f98@nvidia.com>
Date: Thu, 8 Jan 2026 17:57:35 +0530
From: Kartik Rajput <kkartik@...dia.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: lenb@...nel.org, sakari.ailus@...ux.intel.com,
 mika.westerberg@...ux.intel.com, thierry.reding@...il.com,
 jonathanh@...dia.com, linux-acpi@...r.kernel.org,
 linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] ACPI: bus: Use OF match data for PRP0001 matched
 devices

Hi Andy,

Thanks for reviewing the patch!

On 07/01/26 21:17, Andy Shevchenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> On Wed, Jan 07, 2026 at 05:33:18PM +0530, Kartik Rajput wrote:
>> When a device is matched via PRP0001, the driver's OF (DT) match table
>> must be used to obtain the device match data. If a driver provides both
>> an acpi_match_table and an of_match_table, the current
>> acpi_device_get_match_data() path consults the driver's acpi_match_table
>> and returns NULL (no ACPI ID matches).
> 
> Since we have both tables, why the actual ACPI HID of the device in question
> (actually which one?) can't be used?
> 
>> Explicitly detect PRP0001 and fetch match data from the driver's
>> of_match_table via acpi_of_device_get_match_data().
> 
> In principle we can go this way, but can you tell a bit more of a story?
> Why the device in question can't use existed or a newly allocated ACPI HID for
> that?
> 

While testing PRP0001-based matching with the Tegra fuse driver on an SoC that does
not yet have an allocated ACPI HID, device_get_match_data() returned NULL because
the driver also provides an acpi_match_table.

Commit 886ca88be6b3 ("ACPI / bus: Respect PRP0001 when retrieving device match data")
was intended to address this by honoring PRP0001 when retrieving match data. However,
when a driver provides an ACPI match table, acpi_device_get_match_data() currently
consults only that table, resulting in NULL match data despite a successful
PRP0001 match.

> ...
> 
>> @@ -1031,8 +1031,9 @@ const void *acpi_device_get_match_data(const struct device *dev)
>>   {
>>        const struct acpi_device_id *acpi_ids = dev->driver->acpi_match_table;
>>        const struct acpi_device_id *match;
>> +     struct acpi_device *adev = ACPI_COMPANION(dev);
> 
> Please, keep it in reversed xmas tree order.
> 

Ack. I will update this in the next revision.

Thanks,
Kartik