Re: [PATCH v2] vsp1: fix video output on R8A77970

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Hello!

On 01/15/2018 03:51 PM, Laurent Pinchart wrote:

On Tuesday, 26 December 2017 23:14:12 EET Sergei Shtylyov wrote:
Laurent has added support for the VSP2-D found on R-Car V3M (R8A77970) but

I'm not sure there's a need to state my name in the commit message.

You were the author of the patch this one has in the Fixes: tag, so I thought that was appropriate. I can remove that if you don't want you name mentioned...

the video  output that VSP2-D sends to DU has a greenish garbage-like line

Why does the text in your patches (commit message, comments, ...) sometime
have double spaces between words ?

   The text looks more pleasant (at least to me). Can remove them if you want...

repeated every 8 or so screen rows.

Is it every "8 or so" rows, or exactly every 8 rows ?

   You really want me to count the pixels?

It turns out that V3M has a teeny LIF register (at least it's documented!)
that you need to set to some kind of a  magic value for the LIF to work
correctly...

Based on the original (and large) patch by Daisuke Matsushita
<daisuke.matsushita.ns@xxxxxxxxxxx>.

What else is in the big patch ? Is it available somewhere ?

Assorted changes gathered together only because they all bring the support for R8A77970. If you're really curious, here you are:

https://github.com/CogentEmbedded/meta-rcar/blob/v2.12.0/meta-rcar-gen3/recipes-kernel/linux/linux-renesas/0030-arm64-renesas-r8a7797-Add-Renesas-R8A7797-SoC-suppor.patch

Fixes: d455b45f8393 ("v4l: vsp1: Add support for new VSP2-BS, VSP2-DL and
VSP2-D instances")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

---
This patch is against the 'media_tree.git' repo's 'master' branch.

Changes in version 2:
- added a  comment before the V3M SoC check;
- fixed indetation in that check;
- reformatted  the patch description.

  drivers/media/platform/vsp1/vsp1_lif.c  |   12 ++++++++++++
  drivers/media/platform/vsp1/vsp1_regs.h |    5 +++++
  2 files changed, 17 insertions(+)

Index: media_tree/drivers/media/platform/vsp1/vsp1_lif.c
===================================================================
--- media_tree.orig/drivers/media/platform/vsp1/vsp1_lif.c
+++ media_tree/drivers/media/platform/vsp1/vsp1_lif.c
@@ -155,6 +155,18 @@ static void lif_configure(struct vsp1_en
  			(obth << VI6_LIF_CTRL_OBTH_SHIFT) |
  			(format->code == 0 ? VI6_LIF_CTRL_CFMT : 0) |
  			VI6_LIF_CTRL_REQSEL | VI6_LIF_CTRL_LIF_EN);
+
+	/*
+	 * R-Car V3M has the buffer attribute register you absolutely need
+	 * to write kinda magic value to  for the LIF to work correctly...
+	 */

I'm not sure about the "kinda" magic value. 1536 is very likely a buffer size.

Well, that's only guessing. The manual doesn't say anything about what the number is.

How about the following text ?

	/*
	 * On V3M the LBA register has to be set to a non-default value to

   I'd then spell its full name, LIF0 Buffer Attribute register.

	 * guarantee proper operation (otherwise artifacts may appear on the
	 * output). The value required by the datasheet is not documented but
	 * is likely a buffer size or threshold.
	 */
>

   OK,  can change that (modulo the name).

The commit message should also be updated to feel a bit less magic.

   I'll see about it.

+	if ((entity->vsp1->version &
+	     (VI6_IP_VERSION_MODEL_MASK | VI6_IP_VERSION_SOC_MASK)) ==
+	    (VI6_IP_VERSION_MODEL_VSPD_V3 | VI6_IP_VERSION_SOC_V3M)) {
+		vsp1_lif_write(lif, dl, VI6_LIF_LBA,
+			       VI6_LIF_LBA_LBA0 |
+			       (1536 << VI6_LIF_LBA_LBA1_SHIFT));
+	}
  }

The datasheet documents the register as being present on both V3M and M3-W
(and the test I've just run on H3 shows that the register is present there as
well). Should we program it on M3-W or leave it to the default value that
should be what is recommended by the datasheet for that SoC ?

If the default value matches what's recommended by the manual, then I'd leave the register alone. But my task was R8A77970 support only anyway...


[..]

MBR, Sergei



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