Re: [greybus-dev] [PATCH 3/3] [PATCH] staging: greybus: __u8 is sufficient for snd_ctl_elem_type_t and snd_ctl_elem_iface_t

From: Coiby Xu <coiby.xu@gmail.com>
To: Alex Elder <elder@linaro.org>
Cc: David Laight <David.Laight@aculab.com>,
	"devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
	"moderated list:SOUND" <alsa-devel@alsa-project.org>,
	Alex Elder <elder@kernel.org>, Takashi Iwai <tiwai@suse.com>,
	Johan Hovold <johan@kernel.org>,
	"moderated list:GREYBUS SUBSYSTEM" <greybus-dev@lists.linaro.org>,
	Jaroslav Kysela <perex@perex.cz>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [greybus-dev] [PATCH 3/3] [PATCH] staging: greybus: __u8 is sufficient for snd_ctl_elem_type_t and snd_ctl_elem_iface_t
Date: Sat, 26 Sep 2020 12:01:08 +0800	[thread overview]
Message-ID: <20200926040108.otqei3k74gipotk6@Rk> (raw)
In-Reply-To: <160c222d-79e4-c5f0-344f-1a69821db039@linaro.org>

On Fri, Sep 25, 2020 at 11:02:23AM -0500, Alex Elder wrote:
>On 9/25/20 9:11 AM, Coiby Xu wrote:
>>On Thu, Sep 24, 2020 at 10:54:50AM +0000, David Laight wrote:
>>>From: Coiby Xu
>>>>Sent: 24 September 2020 11:21
>>>>Use __8 to replace int and remove the unnecessary __bitwise type
>>>>attribute.
>>>>
>>>>Found by sparse,
>>>...
>>>>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 */
>>>
>>>WTF is all that about anyway??
>>>What is wrong with:
>>>#define    SNDRV_CTL_ELEM_TYPE_NONE    0u /* invalid */
>>
>>I'm sorry I don't quite understand you. Are you suggesting
>>SNDRV_CTL_ELEM_TYPE_NONE
>>isn't needed in the first place?
>
>I think David is asking why it's defined the way it is,
>and I'd guess it's to have the compiler issue an error
>if you attempt to assign one of these values to a variable
>or field of the wrong type.
>
>No, you should not attempt to change this.

Thank you for the explanation!

>
>					-Alex
>>>    David
>>>
>>>-
>>>Registered Address Lakeside, Bramley Road, Mount Farm, Milton
>>>Keynes, MK1 1PT, UK
>>>Registration No: 1397386 (Wales)
>>>
>>
>>--
>>Best regards,
>>Coiby
>>_______________________________________________
>>greybus-dev mailing list
>>greybus-dev@lists.linaro.org
>>https://lists.linaro.org/mailman/listinfo/greybus-dev
>

--
Best regards,
Coiby