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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	kernel@collabora.com, linux-media@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 19/24] media: rkvdec-h264: Add field decoding support
Date: Wed, 30 Mar 2022 18:16:58 +0300	[thread overview]
Message-ID: <20220330151658.GV12805@kadam> (raw)
In-Reply-To: <ed16a4dcfb0859a284675ddad46ab536008a15c5.camel@collabora.com>

Yeah.  I'm aboslutely fine with whatever you do.  Some of the questions
you're asking occurred to me too but I don't have the answers.

> > > > > +		for (i = 0; i < builder->num_valid; i++) {
> > > > > +			struct v4l2_h264_reference *ref;
> > > > > +			u8 dpb_valid;
> > > > > +			u8 bottom;
> > > > 
> > > > These would be better as type bool.
> > > 
> > > I never used a bool for bit operations before, but I guess that can work, thanks
> > > for the suggestion. As this deviates from the original code, I suppose I should
> > > make this a separate patch ?
> > 
> > I just saw the name and wondered why it was a u8.  bool does make more
> > sense and works fine for the bitwise stuff.  But I don't really care at
> > all.
> 
> I'll do that in v2, in same patch, looks minor enough. I think if using bool
> could guaranty that only 1 or 0 is  possible, it would be even better, but don't
> think C works like this.

I'm not sure I understand.  If you assign "bool x = <any non-zero>;"
then x is set to true.  Do you want a static checker warning for if
<any non-zero> can be something other than one or zero?  The problem is
that people sometimes deliberately do stuff like "bool x = var & 0xf0;".
Smatch will complain if you assign a negative value to x.

test.c:8 test() warn: assigning (-3) to unsigned variable 'x'

It's supposed to print a warning if you used it to save error codes like:

	x = some_kernel_function();

But it does not.  :/  Something to investigate.

regards,
dan carpenter


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	kernel@collabora.com, linux-media@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 19/24] media: rkvdec-h264: Add field decoding support
Date: Wed, 30 Mar 2022 18:16:58 +0300	[thread overview]
Message-ID: <20220330151658.GV12805@kadam> (raw)
In-Reply-To: <ed16a4dcfb0859a284675ddad46ab536008a15c5.camel@collabora.com>

Yeah.  I'm aboslutely fine with whatever you do.  Some of the questions
you're asking occurred to me too but I don't have the answers.

> > > > > +		for (i = 0; i < builder->num_valid; i++) {
> > > > > +			struct v4l2_h264_reference *ref;
> > > > > +			u8 dpb_valid;
> > > > > +			u8 bottom;
> > > > 
> > > > These would be better as type bool.
> > > 
> > > I never used a bool for bit operations before, but I guess that can work, thanks
> > > for the suggestion. As this deviates from the original code, I suppose I should
> > > make this a separate patch ?
> > 
> > I just saw the name and wondered why it was a u8.  bool does make more
> > sense and works fine for the bitwise stuff.  But I don't really care at
> > all.
> 
> I'll do that in v2, in same patch, looks minor enough. I think if using bool
> could guaranty that only 1 or 0 is  possible, it would be even better, but don't
> think C works like this.

I'm not sure I understand.  If you assign "bool x = <any non-zero>;"
then x is set to true.  Do you want a static checker warning for if
<any non-zero> can be something other than one or zero?  The problem is
that people sometimes deliberately do stuff like "bool x = var & 0xf0;".
Smatch will complain if you assign a negative value to x.

test.c:8 test() warn: assigning (-3) to unsigned variable 'x'

It's supposed to print a warning if you used it to save error codes like:

	x = some_kernel_function();

But it does not.  :/  Something to investigate.

regards,
dan carpenter


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  reply	other threads:[~2022-03-30 15:17 UTC|newest]

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-28 19:59 [PATCH v1 00/24] H.264 Field Decoding Support for Frame-based Decoders Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 01/24] media: h264: Increase reference lists size to 32 Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29  8:25   ` Sebastian Fricke
2022-03-29  8:25     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 02/24] media: doc: Document dual use of H.264 pic_num/frame_num Nicolas Dufresne
2022-03-29  8:32   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 03/24] media: h264: Avoid wrapping long_term_frame_idx Nicolas Dufresne
2022-03-29  8:35   ` Sebastian Fricke
2022-03-31 16:28     ` Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 04/24] media: h264: Store current picture fields Nicolas Dufresne
2022-03-29  9:07   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 05/24] media: h264: Store all fields into the unordered list Nicolas Dufresne
2022-03-29 12:57   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 06/24] media: v4l2: Trace calculated p/b0/b1 initial reflist Nicolas Dufresne
2022-03-29 15:08   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 07/24] media: h264: Sort p/b reflist using frame_num Nicolas Dufresne
2022-03-29 13:34   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 08/24] media: v4l2: Reorder field reflist Nicolas Dufresne
2022-03-29 13:54   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 09/24] media: v4l2-mem2mem: Fix typo in trace message Nicolas Dufresne
2022-03-29 13:57   ` Sebastian Fricke
2022-03-30 14:57     ` Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 10/24] media: v4l2-mem2mem: Trace on implicit un-hold Nicolas Dufresne
2022-03-29 13:58   ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 11/24] media: videobuf2-v4l2: Warn on holding buffers without support Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 12/24] media: rkvdec: Stop overclocking the decoder Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29 15:15   ` Sebastian Fricke
2022-03-29 15:15     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 13/24] media: rkvdec: h264: Fix reference frame_num wrap for second field Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29 15:17   ` Sebastian Fricke
2022-03-29 15:17     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 14/24] media: rkvdec: h264: Fix dpb_valid implementation Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29 15:27   ` Sebastian Fricke
2022-03-29 15:27     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 15/24] media: rkvdec: Enable capture buffer holding for H264 Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29 15:34   ` Sebastian Fricke
2022-03-29 15:34     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 16/24] media: rkvdec: Ensure decoded resolution fit coded resolution Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29 15:39   ` Sebastian Fricke
2022-03-29 15:39     ` Sebastian Fricke
2022-03-30  9:06     ` Sebastian Fricke
2022-03-30  9:06       ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 17/24] media: rkvdec: h264: Validate and use pic width and height in mbs Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  6:48   ` Sebastian Fricke
2022-03-30  6:48     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 18/24] media: rkvdec: h264: Fix bit depth wrap in pps packet Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  6:59   ` Sebastian Fricke
2022-03-30  6:59     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 19/24] media: rkvdec-h264: Add field decoding support Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29  8:13   ` Dan Carpenter
2022-03-29  8:13     ` Dan Carpenter
2022-03-29 20:54     ` Nicolas Dufresne
2022-03-29 20:54       ` Nicolas Dufresne
2022-03-30  5:15       ` Dan Carpenter
2022-03-30  5:15         ` Dan Carpenter
2022-03-30 13:39         ` Nicolas Dufresne
2022-03-30 13:39           ` Nicolas Dufresne
2022-03-30 15:16           ` Dan Carpenter [this message]
2022-03-30 15:16             ` Dan Carpenter
2022-03-31 13:40             ` Nicolas Dufresne
2022-03-31 13:40               ` Nicolas Dufresne
2022-03-30  7:10   ` Sebastian Fricke
2022-03-30  7:10     ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 20/24] media: hantro: Enable HOLD_CAPTURE_BUF for H.264 Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  7:36   ` Sebastian Fricke
2022-03-30  7:36     ` Sebastian Fricke
2022-03-31 18:25     ` Nicolas Dufresne
2022-03-31 18:25       ` Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 21/24] media: hantro: Stop using H.264 parameter pic_num Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  7:42   ` Sebastian Fricke
2022-03-30  7:42     ` Sebastian Fricke
2022-03-30 15:08     ` Nicolas Dufresne
2022-03-30 15:08       ` Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 22/24] media: hantro: h264: Make dpb entry management more robust Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  7:59   ` Sebastian Fricke
2022-03-30  7:59     ` Sebastian Fricke
2022-03-30 15:15     ` Nicolas Dufresne
2022-03-30 15:15       ` Nicolas Dufresne
2022-03-30 23:43       ` Ezequiel Garcia
2022-03-30 23:43         ` Ezequiel Garcia
2022-03-31  6:54         ` Sebastian Fricke
2022-03-31  6:54           ` Sebastian Fricke
2022-03-28 19:59 ` [PATCH v1 23/24] media: hantro: Add H.264 field decoding support Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-30  9:03   ` Sebastian Fricke
2022-03-30  9:03     ` Sebastian Fricke
2022-03-30 15:25     ` Nicolas Dufresne
2022-03-30 15:25       ` Nicolas Dufresne
2022-03-28 19:59 ` [PATCH v1 24/24] media: rkvdec-h264: Don't hardcode SPS/PPS parameters Nicolas Dufresne
2022-03-28 19:59   ` Nicolas Dufresne
2022-03-29  7:22   ` Sebastian Fricke
2022-03-29  7:22     ` Sebastian Fricke
2022-03-30 15:27     ` Nicolas Dufresne
2022-03-30 15:27       ` Nicolas Dufresne

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