[linux-sunxi] Re: [PATCH v3 10/24] drm/sun4i: tcon: Generalize engine search algorithm

On Sun, Jul 01, 2018 at 09:09:47PM +0200, Jernej ?krabec wrote:

Dne petek, 29. junij 2018 ob 21:06:09 CEST je Jernej ?krabec napisal(a):

quoted

Dne ?etrtek, 28. junij 2018 ob 20:25:43 CEST je Maxime Ripard napisal(a):

quoted

On Thu, Jun 28, 2018 at 06:48:50AM +0200, Jernej ?krabec wrote:

quoted

Dne ?etrtek, 28. junij 2018 ob 04:06:52 CEST je Chen-Yu Tsai napisal(a):

quoted

On Mon, Jun 25, 2018 at 8:02 PM, Jernej Skrabec
[off-list ref]

wrote:

quoted

quoted

Current "old" method to find engine worked pretty well for DE2.
However,
it doesn't work when TCON TOP is between  mixer (engine) and TCON.
TCON
TOP has multiple input ports, but current engine search algorithm
expects only one.

This can be fixed by first looking for output port id and selecting
matching input by subtracting 1 for the next round. This work even
if
there is only one input and output.

Signed-off-by: Jernej Skrabec <redacted>
---

 drivers/gpu/drm/sun4i/sun4i_tcon.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c

b/drivers/gpu/drm/sun4i/sun4i_tcon.c index
08747fc3ee71..264bcc43da11
100644

--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -791,12 +791,14 @@ static int sun4i_tcon_init_regmap(struct

device
*dev,

  */
 
 static struct sunxi_engine *
 sun4i_tcon_find_engine_traverse(struct sun4i_drv *drv,

-                               struct device_node *node)
+                               struct device_node *node,
+                               u32 port_id)

 {
 
        struct device_node *port, *ep, *remote;
        struct sunxi_engine *engine = ERR_PTR(-EINVAL);

+       u32 reg = 0;

-       port = of_graph_get_port_by_id(node, 0);
+       port = of_graph_get_port_by_id(node, port_id);

        if (!port)
        
                return ERR_PTR(-EINVAL);

@@ -826,8 +828,20 @@ sun4i_tcon_find_engine_traverse(struct

sun4i_drv
*drv,

                if (remote == engine->node)
                
                        goto out_put_remote;

+       /*
+        * According to device tree binding input ports have even id
+        * number and output ports have odd id. Since component with
+        * more than one input and one output (TCON TOP) exits,
correct
+        * remote input id has to be calculated by subtracting 1
from
+        * remote output id. If this for some reason can't be done,
0
+        * is used as input port id.
+        */

You need to call

    of_node_put(port);

to drop the reference to the original port.

Thanks for noticing it. I guess I should send fix patch, since patches
from
drm-misc-next can't be dropped.

Yeah, please send additional patches for all the issues pointed out by
Chen-Yu.

Of course. I hope this can be resolved till the end of the next week. After
that, I will be away from PC for 2 weeks. Feel free to drop DT patches if
you think that it will come too close to merge window.

Actually, can you drop it anyway? It needs a lot of changes and keeping HDMI 
working would need some effort.

No, we can't drop it, unfortunately.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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