On Thu, Sep 24, 2020 at 01:00:57PM +0200, Greg Kroah-Hartman wrote:
On Thu, Sep 24, 2020 at 06:20:39PM +0800, Coiby Xu wrote:Use __8 to replace int and remove the unnecessary __bitwise type attribute. Found by sparse, $ make C=2 drivers/staging/greybus/ drivers/staging/greybus/audio_topology.c:185:24: warning: cast to restricted snd_ctl_elem_type_t drivers/staging/greybus/audio_topology.c:679:14: warning: restricted snd_ctl_elem_iface_t degrades to integer drivers/staging/greybus/audio_topology.c:906:14: warning: restricted snd_ctl_elem_iface_t degrades to integer Signed-off-by: Coiby Xu <coiby.xu@xxxxxxxxx> --- drivers/staging/greybus/audio_topology.c | 2 +- include/uapi/sound/asound.h | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/staging/greybus/audio_topology.c b/drivers/staging/greybus/audio_topology.c index 56bf1a4f95ad..f6023ff390c2 100644 --- a/drivers/staging/greybus/audio_topology.c +++ b/drivers/staging/greybus/audio_topology.c @@ -182,7 +182,7 @@ static int gbcodec_mixer_ctl_info(struct snd_kcontrol *kcontrol, /* update uinfo */ uinfo->access = data->access; uinfo->count = data->vcount; - uinfo->type = (snd_ctl_elem_type_t)info->type; + uinfo->type = info->type; switch (info->type) { case GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN: diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 535a7229e1d9..8e71a95644ab 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -950,7 +950,7 @@ struct snd_ctl_card_info { unsigned char components[128]; /* card components / fine identification, delimited with one space (AC97 etc..) */ }; -typedef int __bitwise snd_ctl_elem_type_t; +typedef __u8 snd_ctl_elem_type_t; #define SNDRV_CTL_ELEM_TYPE_NONE ((__force snd_ctl_elem_type_t) 0) /* invalid */ #define SNDRV_CTL_ELEM_TYPE_BOOLEAN ((__force snd_ctl_elem_type_t) 1) /* boolean type */ #define SNDRV_CTL_ELEM_TYPE_INTEGER ((__force snd_ctl_elem_type_t) 2) /* integer type */ @@ -960,7 +960,7 @@ typedef int __bitwise snd_ctl_elem_type_t; #define SNDRV_CTL_ELEM_TYPE_INTEGER64 ((__force snd_ctl_elem_type_t) 6) /* 64-bit integer type */ #define SNDRV_CTL_ELEM_TYPE_LAST SNDRV_CTL_ELEM_TYPE_INTEGER64 -typedef int __bitwise snd_ctl_elem_iface_t; +typedef __u8 snd_ctl_elem_iface_t; #define SNDRV_CTL_ELEM_IFACE_CARD ((__force snd_ctl_elem_iface_t) 0) /* global control */ #define SNDRV_CTL_ELEM_IFACE_HWDEP ((__force snd_ctl_elem_iface_t) 1) /* hardware dependent device */ #define SNDRV_CTL_ELEM_IFACE_MIXER ((__force snd_ctl_elem_iface_t) 2) /* virtual mixer device */I can't take a uapi sound header file patch along with a driver change, these need to be independant.
Thank you and Alex for reminding me this is a change of public header!
And this is a userspace api, you just changed the size of an externally facing variable, are you _SURE_ that is ok to do?
The reasons I make this change are, 1) using int to represent 7 enumeration
values seems to be overkill; 2) using one type could avoid worries
about byte order.
I examine one userspace example (libalsa-intf/alsa_mixer.c [1]). This
change won't cause compiling breakage. But I don't the experience to
imagine any other bad consequence.
Another way to avoid userspace API change is to let
"struct gb_audio_ctl_elem_info" use snd_ctl_elem_iface_t type which may
be more elegant than using "__force" as suggested by Alex,
$ git diff
diff --git a/include/linux/greybus/greybus_protocols.h b/include/linux/greybus/greybus_protocols.h
index aeb8f9243545..7f6753ec7ef7 100644
--- a/include/linux/greybus/greybus_protocols.h
+++ b/include/linux/greybus/greybus_protocols.h
@@ -8,6 +8,7 @@
#define __GREYBUS_PROTOCOLS_H
#include <linux/types.h>
+#include <sound/asound.h>
/* Fixed IDs for control/svc protocols */
@@ -1997,7 +1998,7 @@ struct gb_audio_enumerated {
} __packed;
struct gb_audio_ctl_elem_info { /* See snd_ctl_elem_info in Linux source */
- __u8 type; /* GB_AUDIO_CTL_ELEM_TYPE_* */
+ snd_ctl_elem_type_t type; /* GB_AUDIO_CTL_ELEM_TYPE_* */
__le16 dimen[4];
union {
struct gb_audio_integer integer
My only concern is if greybus authors have any special reason to not include
sound/asound.h in the first place and re-define things like SNDRV_CTL_ELEM_TYPE_*,
/* See SNDRV_CTL_ELEM_TYPE_* in Linux source */
#define GB_AUDIO_CTL_ELEM_TYPE_BOOLEAN 0x01
#define GB_AUDIO_CTL_ELEM_TYPE_INTEGER 0x02
/* See SNDRV_CTL_ELEM_IFACE_* in Linux source */
#define GB_AUDIO_CTL_ELEM_IFACE_CARD 0x00
...
/* SNDRV_CTL_ELEM_ACCESS_* in Linux source */
#define GB_AUDIO_ACCESS_READ BIT(0)
...
[1] https://gitlab.com/Codeaurora/platform_hardware_qcom_audio/-/blob/aee6032826ec7c8b6edda404422fda0ef40ec2db/libalsa-intf/alsa_mixer.c
alsa_mixer.c
thanks, greg k-h
-- Best regards, Coiby _______________________________________________ greybus-dev mailing list greybus-dev@xxxxxxxxxxxxxxxx https://lists.linaro.org/mailman/listinfo/greybus-dev
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