[PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[Uwe Kleine-König (The Capable Hub)]

To match how device-id array terminators look like for other device
types drop `.id = ""` from it and let the compiler care for zeroing the
entry.

There are no changes in the compiled drivers, only the source looks
nicer.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
 sound/drivers/mpu401/mpu401.c | 2 +-
 sound/isa/cs423x/cs4236.c     | 2 +-
 sound/isa/es18xx.c            | 2 +-
 sound/isa/opl3sa2.c           | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/drivers/mpu401/mpu401.c b/sound/drivers/mpu401/mpu401.c
index b615a310c79a..c217c427bf1e 100644
--- a/sound/drivers/mpu401/mpu401.c
+++ b/sound/drivers/mpu401/mpu401.c
@@ -123,7 +123,7 @@ static struct platform_driver snd_mpu401_driver = {
 
 static const struct pnp_device_id snd_mpu401_pnpids[] = {
 	{ .id = "PNPb006" },
-	{ .id = "" }
+	{ }
 };
 
 MODULE_DEVICE_TABLE(pnp, snd_mpu401_pnpids);
diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
index 238065ffa1d2..ecce31b348b0 100644
--- a/sound/isa/cs423x/cs4236.c
+++ b/sound/isa/cs423x/cs4236.c
@@ -94,7 +94,7 @@ static const struct pnp_device_id snd_cs423x_pnpbiosids[] = {
 	/* Guillemot Turtlebeach something appears to be cs4232 compatible
 	 * (untested) */
 	{ .id = "GIM0100" },
-	{ .id = "" }
+	{ }
 };
 MODULE_DEVICE_TABLE(pnp, snd_cs423x_pnpbiosids);
 
diff --git a/sound/isa/es18xx.c b/sound/isa/es18xx.c
index 1a02da1679d0..3cadbf7cf238 100644
--- a/sound/isa/es18xx.c
+++ b/sound/isa/es18xx.c
@@ -1935,7 +1935,7 @@ static int pnpc_registered __ro_after_init;
 static const struct pnp_device_id snd_audiodrive_pnpbiosids[] = {
 	{ .id = "ESS1869" },
 	{ .id = "ESS1879" },
-	{ .id = "" }		/* end */
+	{ }			/* end */
 };
 
 MODULE_DEVICE_TABLE(pnp, snd_audiodrive_pnpbiosids);
diff --git a/sound/isa/opl3sa2.c b/sound/isa/opl3sa2.c
index 88eada933a1f..66b1e361c101 100644
--- a/sound/isa/opl3sa2.c
+++ b/sound/isa/opl3sa2.c
@@ -125,7 +125,7 @@ struct snd_opl3sa2 {
 static const struct pnp_device_id snd_opl3sa2_pnpbiosids[] = {
 	{ .id = "YMH0021" },
 	{ .id = "NMX2210" },	/* Gateway Solo 2500 */
-	{ .id = "" }		/* end */
+	{ }			/* end */
 };
 
 MODULE_DEVICE_TABLE(pnp, snd_opl3sa2_pnpbiosids);

base-commit: a87737435cfa134f9cdcc696ba3080759d04cf72
-- 
2.47.3

Re: [PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[Jaroslav Kysela]

On 6/9/26 18:46, Uwe Kleine-König (The Capable Hub) wrote:
> To match how device-id array terminators look like for other device
> types drop `.id = ""` from it and let the compiler care for zeroing the
> entry.
> 
> There are no changes in the compiled drivers, only the source looks
> nicer.

It's not true. Unless the matching and lookup functions are not changed, 
there's difference between NULL pointer and pointer to an empty string.

See match_device in drivers/pnp/driver.c - "while (*drv_id->id)". Your change 
will cause NULL pointer dereference.

					Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.

Re: [PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[Uwe Kleine-König (The Capable Hub)]

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On Tue, Jun 09, 2026 at 08:38:57PM +0200, Jaroslav Kysela wrote:
> On 6/9/26 18:46, Uwe Kleine-König (The Capable Hub) wrote:
> > To match how device-id array terminators look like for other device
> > types drop `.id = ""` from it and let the compiler care for zeroing the
> > entry.
> > 
> > There are no changes in the compiled drivers, only the source looks
> > nicer.
> 
> It's not true. Unless the matching and lookup functions are not changed,
> there's difference between NULL pointer and pointer to an empty string.
> 
> See match_device in drivers/pnp/driver.c - "while (*drv_id->id)". Your
> change will cause NULL pointer dereference.

That's an easy but wrong diagnosis that I fell for first, too. Note that
.id is not a pointer but a char array.

Best regards
Uwe

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Re: [PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[Jaroslav Kysela]

On 6/9/26 21:20, Uwe Kleine-König (The Capable Hub) wrote:
> On Tue, Jun 09, 2026 at 08:38:57PM +0200, Jaroslav Kysela wrote:
>> On 6/9/26 18:46, Uwe Kleine-König (The Capable Hub) wrote:
>>> To match how device-id array terminators look like for other device
>>> types drop `.id = ""` from it and let the compiler care for zeroing the
>>> entry.
>>>
>>> There are no changes in the compiled drivers, only the source looks
>>> nicer.
>>
>> It's not true. Unless the matching and lookup functions are not changed,
>> there's difference between NULL pointer and pointer to an empty string.
>>
>> See match_device in drivers/pnp/driver.c - "while (*drv_id->id)". Your
>> change will cause NULL pointer dereference.
> 
> That's an easy but wrong diagnosis that I fell for first, too. Note that
> .id is not a pointer but a char array.

Right. Apologize for the noise. Thanks

				Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.

Re: [PATCH v1] ALSA: Improve style of pnp_device_id array terminators

[Takashi Iwai]

On Tue, 09 Jun 2026 18:46:10 +0200,
Uwe Kleine-König (The Capable Hub) wrote:
> 
> To match how device-id array terminators look like for other device
> types drop `.id = ""` from it and let the compiler care for zeroing the
> entry.
> 
> There are no changes in the compiled drivers, only the source looks
> nicer.
> 
> Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>

Applied to for-next branch now.  Thanks.


Takashi