From: Pekka Paalanen <ppaalanen@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>, Petr Mladek <pmladek@suse.com>,
Dave Stevenson <dave.stevenson@raspberrypi.com>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
laurent.pinchart@ideasonboard.com,
Sakari Ailus <sakari.ailus@linux.intel.com>,
mchehab@kernel.org, linux-media@vger.kernel.org
Subject: Re: [PATCH 1/1] lib/vsprintf: Add support for printing V4L2 and DRM fourccs
Date: Mon, 6 Apr 2020 10:37:58 +0300 [thread overview]
Message-ID: <20200406103758.1be49f78@eldfell.localdomain> (raw)
In-Reply-To: <20200401151332.GU1922688@smile.fi.intel.com>
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On Wed, 1 Apr 2020 18:13:32 +0300
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> On Wed, Apr 01, 2020 at 04:13:51PM +0200, Hans Verkuil wrote:
> > On 4/1/20 4:05 PM, Sakari Ailus wrote:
> > > Add a printk modifier %ppf (for pixel format) for printing V4L2 and DRM
> > > pixel formats denoted by 4ccs. The 4cc encoding is the same for both so
> > > the same implementation can be used.
>
> %p4cc ?
>
> Another possibility
>
> u8 ch[8];
>
> if (*fourcc & BIT(31)) {
> put_unaligned_be32(tmp, &ch[0]);
> strcpy(&ch[4], "-BE");
> } else {
> put_unaligned_le32(tmp, &ch[0]);
> strcpy(&ch[4], "-LE");
> }
> return string(buf, end, &ch[0], spec);
>
Hi,
mind, if I guess right what that code does, I think this would confuse
the fourcc code endianness and the pixel data endianness. I think fourcc
codes are always crafted machine-endian, regardless of how the pixel
data is. At least, that is what drm_fourcc.h seems to be doing with
fourcc_code(). That has nothing to do with DRM_FORMAT_BIG_ENDIAN which
refers to the pixel data.
Thanks,
pq
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next prev parent reply other threads:[~2020-04-06 7:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 14:05 [PATCH 1/1] lib/vsprintf: Add support for printing V4L2 and DRM fourccs Sakari Ailus
2020-04-01 14:13 ` Hans Verkuil
2020-04-01 15:13 ` Andy Shevchenko
2020-04-02 7:32 ` Sakari Ailus
2020-04-06 7:37 ` Pekka Paalanen [this message]
2020-04-02 7:18 ` Sakari Ailus
2020-04-02 8:34 ` Jani Nikula
2020-04-02 8:52 ` Sakari Ailus
2020-04-02 13:53 ` Mauro Carvalho Chehab
2020-04-02 23:28 ` Joe Perches
2020-04-02 23:26 ` Joe Perches
2020-04-03 6:37 ` Jani Nikula
2020-04-03 13:11 ` Joe Perches
2020-04-27 14:50 Sakari Ailus
2020-04-27 14:54 ` Sakari Ailus
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