[PATCH v4 0/6] drm: exynos: dsi: Convert drm bridge
Marek Szyprowski
m.szyprowski at samsung.com
Thu Dec 23 09:15:16 UTC 2021
Hi Jagan,
On 18.12.2021 00:16, Marek Szyprowski wrote:
> On 15.12.2021 15:56, Jagan Teki wrote:
>> On Wed, Dec 15, 2021 at 7:49 PM Marek Szyprowski
>> <m.szyprowski at samsung.com> wrote:
>>> On 15.12.2021 13:57, Jagan Teki wrote:
>>>> On Wed, Dec 15, 2021 at 5:31 PM Marek Szyprowski
>>>> <m.szyprowski at samsung.com> wrote:
>>>>> On 15.12.2021 11:15, Jagan Teki wrote:
>>>>>> Updated series about drm bridge conversion of exynos dsi.
>>>>>> Previous version can be accessible, here [1].
>>>>>>
>>>>>> Patch 1: connector reset
>>>>>>
>>>>>> Patch 2: panel_bridge API
>>>>>>
>>>>>> Patch 3: Bridge conversion
>>>>>>
>>>>>> Patch 4: Atomic functions
>>>>>>
>>>>>> Patch 5: atomic_set
>>>>>>
>>>>>> Patch 6: DSI init in enable
>>>>> There is a little progress! :)
>>>>>
>>>>> Devices with a simple display pipeline (only a DSI panel, like
>>>>> Trats/Trats2) works till the last patch. Then, after applying
>>>>> ("[PATCH
>>>>> v4 6/6] drm: exynos: dsi: Move DSI init in bridge enable"), I get no
>>>>> display at all.
>>>>>
>>>>> A TM2e board with in-bridge (Exynos MIC) stops displaying anything
>>>>> after
>>>>> applying patch "[PATCH v4 2/6] drm: exynos: dsi: Use drm
>>>>> panel_bridge API".
>>>>>
>>>>> In case of the Arndale board with tc358764 bridge, no much
>>>>> progress. The
>>>>> display is broken just after applying the "[PATCH v2] drm: bridge:
>>>>> tc358764: Use drm panel_bridge API" patch on top of linux-next.
>>>>>
>>>>> In all cases the I had "drm: of: Lookup if child node has panel or
>>>>> bridge" patch applied.
>>>> Just skip the 6/6 for now.
>>>>
>>>> Apply
>>>> -
>>>> https://protect2.fireeye.com/v1/url?k=a24f3f76-fdd40659-a24eb439-0cc47a31cdf8-97ea12b4c5258d11&q=1&e=37a169bf-7ca5-4362-aad7-486018c7a708&u=https%3A%2F%2Fpatchwork.amarulasolutions.com%2Fpatch%2F1825%2F
>>>> -
>>>> https://protect2.fireeye.com/v1/url?k=a226360f-fdbd0f20-a227bd40-0cc47a31cdf8-ebd66aebee1058d7&q=1&e=37a169bf-7ca5-4362-aad7-486018c7a708&u=https%3A%2F%2Fpatchwork.amarulasolutions.com%2Fpatch%2F1823%2F
>>>>
>>>> Then apply 1/6 to 5/6. and update the status?
>>> Okay, my fault, I didn't check that case on Arndale.
>>>
>>> I've checked and indeed, Trats/Trats2 and Arndale works after the above
>>> 2 patches AND patches 1-5.
>>>
>>> The only problem is now on TM2e, which uses Exynos MIC as in-bridge for
>>> Exynos DSI:
>>>
>>> [ 4.068866] [drm] Exynos DRM: using 13800000.decon device for DMA
>>> mapping operations
>>> [ 4.069183] exynos-drm exynos-drm: bound 13800000.decon (ops
>>> decon_component_ops)
>>> [ 4.128983] exynos-drm exynos-drm: bound 13880000.decon (ops
>>> decon_component_ops)
>>> [ 4.129261] exynos-drm exynos-drm: bound 13930000.mic (ops
>>> exynos_mic_component_ops)
>>> [ 4.133508] exynos-dsi 13900000.dsi: [drm:exynos_dsi_host_attach]
>>> *ERROR* failed to find the bridge: -19
>>> [ 4.136392] exynos-drm exynos-drm: bound 13900000.dsi (ops
>>> exynos_dsi_component_ops)
>>> [ 4.145499] rc_core: Couldn't load IR keymap rc-cec
>>> [ 4.145666] Registered IR keymap rc-empty
>>> [ 4.148402] rc rc0: sii8620 as /devices/virtual/rc/rc0
>>> [ 4.156051] input: sii8620 as /devices/virtual/rc/rc0/input1
>>> [ 4.160647] exynos-drm exynos-drm: bound 13970000.hdmi (ops
>>> hdmi_component_ops)
>>> [ 4.169923] exynos-drm exynos-drm: [drm] Cannot find any crtc or
>>> sizes
>>> [ 4.173958] exynos-drm exynos-drm: [drm] Cannot find any crtc or
>>> sizes
>>> [ 4.182304] [drm] Initialized exynos 1.1.0 20180330 for
>>> exynos-drm on
>>> minor 0
>>>
>>> The display pipeline for TM2e is:
>>>
>>> Exynos5433 Decon -> Exynos MIC -> Exynos DSI -> s6e3ha2 DSI panel
>> If Trats/Trats2 is working then it has to work. I don't see any
>> difference in output pipeline. Can you please share the full log, I
>> cannot see host_attach print saying "Attached.."
>
> Well, there is a failure message about the panel:
>
> exynos-dsi 13900000.dsi: [drm:exynos_dsi_host_attach] *ERROR* failed
> to find the bridge: -19
>
> however it looks that something might be broken in dts. The in-bridge
> (Exynos MIC) is on port 0 and the panel is @0, what imho might cause
> the issue.
>
> I've tried to change in in-bridge ('mic_to_dsi') port to 1 in
> exynos5433.dtsi. Then the panel has been attached:
>
> exynos-dsi 13900000.dsi: [drm:exynos_dsi_host_attach] Attached s6e3hf2
> device
>
> but the display is still not working, probably due to lack of proper
> Exynos MIC handling. I will investigate it later and let You know.
I've played a bit with the Exynos DRM code and finally I made it working
on TM2(e). There are basically 3 different issues that need to be fixed
to get it working with the $subject patchset:
1. Port numbers in exynos5433 dsi/dts are broken. For all pre-Exynos5433
boards the panel was defined as a DSI node child (at 'reg 0'), what
means it used port 0. Then, Exynos5433 introduced so called RGB-in at
port 0 and panel at port 1 (as described in the dt bindings). However
the committed Exynos5433 dtsi and TM2(e) dts still defined panel as a
DSI child (with reg=0, so port 0) and Exynos MIC as of-graph at port 0.
The Exynos DSI code however always searched for a panel as a DSI child
node, so it worked fine, even though the panel and exynos mic used in
fact the 'port 0'. IMHO this can be fixed by the following patch:
diff --git a/arch/arm64/boot/dts/exynos/exynos5433.dtsi
b/arch/arm64/boot/dts/exynos/exynos5433.dtsi
index bfe4ed8a23d6..2718c752d916 100644
--- a/arch/arm64/boot/dts/exynos/exynos5433.dtsi
+++ b/arch/arm64/boot/dts/exynos/exynos5433.dtsi
@@ -1046,8 +1046,8 @@
#address-cells = <1>;
#size-cells = <0>;
- port at 0 {
- reg = <0>;
+ port at 1 {
+ reg = <1>;
dsi_to_mic: endpoint {
remote-endpoint =
<&mic_to_dsi>;
};
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index d2933a70c01f..e8e2df339c5f 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -220,8 +220,8 @@ enum exynos_dsi_transfer_type {
};
enum {
- DSI_PORT_IN,
- DSI_PORT_OUT
+ DSI_PORT_OUT,
+ DSI_PORT_IN
};
struct exynos_dsi_transfer {
--
2. (devm_)drm_of_get_bridge() ignores panel's 'reg' property and it is
unable to find a panel if there is a 'ports' child node (even if it
describes completely different port than the one requested by the
caller). I don't have time now to fix this, a simple and ugly workaround
for that is to define the complete of-graph for the DSI child panel:
diff --git a/arch/arm64/boot/dts/exynos/exynos5433-tm2e.dts
b/arch/arm64/boot/dts/exynos/exynos5433-tm2e.dts
index 22d26460f3dd..4726c325bd2c 100644
--- a/arch/arm64/boot/dts/exynos/exynos5433-tm2e.dts
+++ b/arch/arm64/boot/dts/exynos/exynos5433-tm2e.dts
@@ -58,6 +58,27 @@
vci-supply = <&ldo28_reg>;
reset-gpios = <&gpg0 0 GPIO_ACTIVE_LOW>;
enable-gpios = <&gpf1 5 GPIO_ACTIVE_HIGH>;
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port at 0 {
+ reg = <0>;
+ panel_to_dsi: endpoint {
+ remote-endpoint = <&dsi_to_panel>;
+ };
+ };
+ };
+ };
+
+ ports {
+ port at 0 {
+ reg = <0>;
+ dsi_to_panel: endpoint {
+ remote-endpoint = <&panel_to_dsi>;
+ };
+ };
};
};
--
3. Lack of proper handling of the 'in-bridge' in the Exynos DSI after
Your conversion. Initially I thought that this could be fixed with the
following simple patch:
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index e8e2df339c5f..2fe9c995549f 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -259,6 +259,7 @@ struct exynos_dsi {
struct mipi_dsi_host dsi_host;
struct drm_bridge bridge;
struct drm_bridge *out_bridge;
+ struct drm_bridge *in_bridge;
struct device *dev;
void __iomem *reg_base;
@@ -1535,7 +1536,7 @@ static int exynos_dsi_host_attach(struct
mipi_dsi_host *host,
drm_bridge_add(&dsi->bridge);
- drm_bridge_attach(encoder, &dsi->bridge, NULL, 0);
+ drm_bridge_attach(encoder, &dsi->bridge, dsi->in_bridge, 0);
/*
* This is a temporary solution and should be made by more
generic way.
@@ -1674,7 +1675,6 @@ static int exynos_dsi_bind(struct device *dev,
struct device *master,
struct drm_encoder *encoder = &dsi->encoder;
struct drm_device *drm_dev = data;
struct device_node *in_bridge_node;
- struct drm_bridge *in_bridge;
int ret;
printk("drm: %s enter\n", __func__);
@@ -1688,9 +1688,10 @@ static int exynos_dsi_bind(struct device *dev,
struct device *master,
}
in_bridge_node = of_graph_get_remote_node(dev->of_node,
DSI_PORT_IN, 0);
if (in_bridge_node) {
- in_bridge = of_drm_find_bridge(in_bridge_node);
- if (in_bridge)
- drm_bridge_attach(encoder, in_bridge, NULL, 0);
+ dsi->in_bridge = of_drm_find_bridge(in_bridge_node);
+ if (dsi->in_bridge) {
+ drm_bridge_attach(encoder, dsi->in_bridge, NULL, 0);
+ }
of_node_put(in_bridge_node);
}
--
but it turned out that in such case the order of the bridge 'enable'
calls is not correct for display pipeline operation. The one that
actually works is (sorry for the hacky code):
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index e8e2df339c5f..51b568556fce 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -259,6 +259,7 @@ struct exynos_dsi {
struct mipi_dsi_host dsi_host;
struct drm_bridge bridge;
struct drm_bridge *out_bridge;
+ struct drm_bridge *in_bridge;
struct device *dev;
void __iomem *reg_base;
@@ -1424,6 +1425,9 @@ static void exynos_dsi_atomic_pre_enable(struct
drm_bridge *bridge,
dsi->state |= DSIM_STATE_ENABLED;
printk("drm: %s finish: %d\n", __func__, 0);
+
+ if (dsi->in_bridge)
+ dsi->in_bridge->funcs->pre_enable(dsi->in_bridge);
}
static void exynos_dsi_atomic_enable(struct drm_bridge *bridge,
@@ -1439,6 +1443,9 @@ static void exynos_dsi_atomic_enable(struct
drm_bridge *bridge,
printk("drm: %s finish: %d\n", __func__, 0);
+ if (dsi->in_bridge)
+ dsi->in_bridge->funcs->enable(dsi->in_bridge);
+
return;
}
@@ -1455,6 +1462,8 @@ static void exynos_dsi_atomic_disable(struct
drm_bridge *bridge,
dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
printk("drm: %s finish: %d\n", __func__, 0);
+ if (dsi->in_bridge)
+ dsi->in_bridge->funcs->disable(dsi->in_bridge);
}
static void exynos_dsi_atomic_post_disable(struct drm_bridge *bridge,
@@ -1470,6 +1479,8 @@ static void exynos_dsi_atomic_post_disable(struct
drm_bridge *bridge,
printk("drm: %s finish: %d\n", __func__, 0);
+ if (dsi->in_bridge)
+ dsi->in_bridge->funcs->post_disable(dsi->in_bridge);
}
static void exynos_dsi_mode_set(struct drm_bridge *bridge,
@@ -1482,6 +1493,10 @@ static void exynos_dsi_mode_set(struct drm_bridge
*bridge,
drm_mode_copy(&dsi->mode, adjusted_mode);
printk("drm: %s finish: %d\n", __func__, ret);
+
+ if (dsi->in_bridge)
+ dsi->in_bridge->funcs->mode_set(dsi->in_bridge, mode,
+ adjusted_mode);
}
static int exynos_dsi_attach(struct drm_bridge *bridge,
@@ -1674,7 +1689,6 @@ static int exynos_dsi_bind(struct device *dev,
struct device *master,
struct drm_encoder *encoder = &dsi->encoder;
struct drm_device *drm_dev = data;
struct device_node *in_bridge_node;
- struct drm_bridge *in_bridge;
int ret;
printk("drm: %s enter\n", __func__);
@@ -1688,9 +1702,11 @@ static int exynos_dsi_bind(struct device *dev,
struct device *master,
}
in_bridge_node = of_graph_get_remote_node(dev->of_node,
DSI_PORT_IN, 0);
if (in_bridge_node) {
- in_bridge = of_drm_find_bridge(in_bridge_node);
- if (in_bridge)
- drm_bridge_attach(encoder, in_bridge, NULL, 0);
+ dsi->in_bridge = of_drm_find_bridge(in_bridge_node);
+ if (dsi->in_bridge) {
+ drm_bridge_attach(encoder, dsi->in_bridge, NULL, 0);
+ INIT_LIST_HEAD(&encoder->bridge_chain);
+ }
of_node_put(in_bridge_node);
}
--
I hope the above findings helps somehow in finishing this patchset. I'm
not deep in the DRM bridge development, but it looks that there is
something seriously broken in the design or Exynos MIC and DSI should
not be modeled as bridges.
I will be on holidays till 10th Jan 2022.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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