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From:   Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc:     linuxarm@huawei.com, mauro.chehab@huawei.com,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Kaixu Xia <kaixuxia@tencent.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Tsuchiya Yuto <kitakar@gmail.com>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        linux-staging@lists.linux.dev
Subject: [PATCH 2/3] media: atomisp: report the visible resolution
Date:   Sun, 31 Oct 2021 11:25:01 +0000
Message-Id: <3a7f0de1edeca8d3e4d91f25f42339580d34a6e0.1635679495.git.mchehab+huawei@kernel.org>
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The atomisp sensors and logic adds an extra pad lines/columns,
called "dvs envelope". It also uses an extra 12 lines/columns
at the sensor for BYT.

As those are not visible to userspace, the V4L2 API should
decrement such values when reporting the current resolution.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/staging/media/atomisp/pci/atomisp_ioctl.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
index 8f0a9a69f075..d92d41dd0ade 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
@@ -876,6 +876,20 @@ static int atomisp_g_fmt_cap(struct file *file, void *fh,
 		v4l2_fill_pix_format(&f->fmt.pix, &fmt.format);
 
 		f->fmt.pix.pixelformat = fmtdesc.pixelformat;
+
+		/*
+		 * HACK: The atomisp does something different here, as it
+		 * seems to set the sensor to a slightly higher resolution than
+		 * the visible ones. That seems to be needed by atomisp's ISP
+		 * in order to properly handle the frames. So, s_fmt adds 16
+		 * extra columns/lines. See atomisp_subdev_set_selection().
+		 *
+		 * Yet, the V4L2 userspace API doesn't expect those, so it
+		 * needs to be decremented when reporting the visible
+		 * resolution to userspace.
+		 */
+		f->fmt.pix.width -= pad_w;
+		f->fmt.pix.height -= pad_h;
 	}
 
 	depth = atomisp_get_pixel_depth(f->fmt.pix.pixelformat);
-- 
2.31.1