linux-kernel - Re: [PATCH 3/6 RESEND] media: mediatek: vcodec: Add a debugfs file to get different useful information

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Date:   Wed, 22 Mar 2023 09:51:19 +0000
From:   Yunfei Dong (董云飞) 
        <Yunfei.Dong@...iatek.com>
To:     "wenst@...omium.org" <wenst@...omium.org>,
        "nfraprado@...labora.com" <nfraprado@...labora.com>,
        "nicolas@...fresne.ca" <nicolas@...fresne.ca>,
        "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>,
        "benjamin.gaignard@...labora.com" <benjamin.gaignard@...labora.com>,
        "hverkuil-cisco@...all.nl" <hverkuil-cisco@...all.nl>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "frkoenig@...omium.org" <frkoenig@...omium.org>,
        "stevecho@...omium.org" <stevecho@...omium.org>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        "hsinyi@...omium.org" <hsinyi@...omium.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>
Subject: Re: [PATCH 3/6 RESEND] media: mediatek: vcodec: Add a debugfs file to
 get different useful information

Hi AngeloGioacchino,

Thanks for your suggestion.
On Mon, 2023-03-20 at 15:49 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Il 20/03/23 11:28, Yunfei Dong ha scritto:
> > In oder to get each instance information according to test command,
> > adding
> > one file node "vdec".
> > 
> > Can use echo command to set different string value as 'echo
> > -picinfo > vdec'
> > to get real and aligned resolution.
> > 
> > Signed-off-by: Yunfei Dong <yunfei.dong@...iatek.com>
> > ---
> >   .../mediatek/vcodec/mtk_vcodec_dbgfs.c        | 85
> > +++++++++++++++++++
> >   .../mediatek/vcodec/mtk_vcodec_dbgfs.h        | 20 +++++
> >   .../mediatek/vcodec/mtk_vcodec_dec_drv.c      |  2 +
> >   3 files changed, 107 insertions(+)
> > 
> > diff --git
> > a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > index bef78c028a75..9e7d57d21cea 100644
> > --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > @@ -10,6 +10,86 @@
> >   #include "mtk_vcodec_drv.h"
> >   #include "mtk_vcodec_util.h"
> > 
> > +static ssize_t mtk_vdec_dbgfs_write(struct file *filp, const char
> > __user *ubuf,
> > +                                 size_t count, loff_t *ppos)
> > +{
> > +     struct mtk_vcodec_dev *vcodec_dev = filp->private_data;
> > +     char buf[32] = { 0 };
> > +     int len, str_count = 0;
> > +     struct mtk_vcodec_dbgfs_inst *dbgfs_inst;
> > +     struct mtk_vcodec_ctx *ctx;
> > +
> > +     len = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos,
> > ubuf, count);
> > +     if (len <= 0)
> > +             return len;
> > +
> > +     list_for_each_entry(dbgfs_inst, &vcodec_dev-
> > >dbgfs.dbgfs_head, node) {
> > +             pr_info("dbgfs_inst id: %d\n", dbgfs_inst->inst_id);
> > +             ctx = dbgfs_inst->vcodec_ctx;
> > +
> > +             if (strstr(buf, "-picinfo")) {
> > +                     str_count++;
> > +                     pr_info("resolution:
> > real(%dx%d)=>align(%dx%d)\n",
> > +                             ctx->picinfo.pic_w, ctx-
> > >picinfo.pic_h,
> > +                             ctx->picinfo.buf_w, ctx-
> > >picinfo.buf_h);
> 
> If you want to use debugfs (which is a good choice!), you should use
> debugfs!
> This means that you shouldn't print this kind of information to the
> kernel,
> but rather to a debugfs entry.
> 
> Example:
> 
> $ echo "-picinfo" > vdec
> $ cat vdec
> 
> resolution: real(1024x768)=>align(something)
> 
> This is the same for all of the commits of this series, so, please
> properly
> use debugfs.
> 
Add new file ops 'read' to get the debug information with cmd "cat
vdec" instead of pr_info.
> 
> Regards,
> Angelo
> 
Best Regards,
Yunfei Dong
>