@@ -105,7 +105,6 @@ struct ps8640 {
struct gpio_desc *gpio_reset;
struct gpio_desc *gpio_powerdown;
struct device_link *link;
- struct edid *edid;
bool pre_enabled;
bool need_post_hpd_delay;
};
@@ -155,23 +154,6 @@ static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux)
return container_of(aux, struct ps8640, aux);
}
-static bool ps8640_of_panel_on_aux_bus(struct device *dev)
-{
- struct device_node *bus, *panel;
-
- bus = of_get_child_by_name(dev->of_node, "aux-bus");
- if (!bus)
- return false;
-
- panel = of_get_child_by_name(bus, "panel");
- of_node_put(bus);
- if (!panel)
- return false;
- of_node_put(panel);
-
- return true;
-}
-
static int _ps8640_wait_hpd_asserted(struct ps8640 *ps_bridge, unsigned long wait_us)
{
struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL];
@@ -539,50 +521,6 @@ static void ps8640_bridge_detach(struct drm_bridge *bridge)
device_link_del(ps_bridge->link);
}
-static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge,
- struct drm_connector *connector)
-{
- struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
- struct device *dev = &ps_bridge->page[PAGE0_DP_CNTL]->dev;
- bool poweroff = !ps_bridge->pre_enabled;
-
- if (!ps_bridge->edid) {
- /*
- * When we end calling get_edid() triggered by an ioctl, i.e
- *
- * drm_mode_getconnector (ioctl)
- * -> drm_helper_probe_single_connector_modes
- * -> drm_bridge_connector_get_modes
- * -> ps8640_bridge_get_edid
- *
- * We need to make sure that what we need is enabled before
- * reading EDID, for this chip, we need to do a full poweron,
- * otherwise it will fail.
- */
- if (poweroff)
- drm_atomic_bridge_chain_pre_enable(bridge,
- connector->state->state);
-
- ps_bridge->edid = drm_get_edid(connector,
- ps_bridge->page[PAGE0_DP_CNTL]->adapter);
-
- /*
- * If we call the get_edid() function without having enabled the
- * chip before, return the chip to its original power state.
- */
- if (poweroff)
- drm_atomic_bridge_chain_post_disable(bridge,
- connector->state->state);
- }
-
- if (!ps_bridge->edid) {
- dev_err(dev, "Failed to get EDID\n");
- return NULL;
- }
-
- return drm_edid_duplicate(ps_bridge->edid);
-}
-
static void ps8640_runtime_disable(void *data)
{
pm_runtime_dont_use_autosuspend(data);
@@ -592,7 +530,6 @@ static void ps8640_runtime_disable(void *data)
static const struct drm_bridge_funcs ps8640_bridge_funcs = {
.attach = ps8640_bridge_attach,
.detach = ps8640_bridge_detach,
- .get_edid = ps8640_bridge_get_edid,
.atomic_post_disable = ps8640_atomic_post_disable,
.atomic_pre_enable = ps8640_atomic_pre_enable,
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
@@ -705,14 +642,6 @@ static int ps8640_probe(struct i2c_client *client)
ps_bridge->bridge.of_node = dev->of_node;
ps_bridge->bridge.type = DRM_MODE_CONNECTOR_eDP;
- /*
- * In the device tree, if panel is listed under aux-bus of the bridge
- * node, panel driver should be able to retrieve EDID by itself using
- * aux-bus. So let's not set DRM_BRIDGE_OP_EDID here.
- */
- if (!ps8640_of_panel_on_aux_bus(&client->dev))
- ps_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
-
/*
* Get MIPI DSI resources early. These can return -EPROBE_DEFER so
* we want to get them out of the way sooner.
@@ -777,13 +706,6 @@ static int ps8640_probe(struct i2c_client *client)
return ret;
}
-static void ps8640_remove(struct i2c_client *client)
-{
- struct ps8640 *ps_bridge = i2c_get_clientdata(client);
-
- kfree(ps_bridge->edid);
-}
-
static const struct of_device_id ps8640_match[] = {
{ .compatible = "parade,ps8640" },
{ }
@@ -792,7 +714,6 @@ MODULE_DEVICE_TABLE(of, ps8640_match);
static struct i2c_driver ps8640_driver = {
.probe = ps8640_probe,
- .remove = ps8640_remove,
.driver = {
.name = "ps8640",
.of_match_table = ps8640_match,
In order to read the EDID from an eDP panel, you not only need to power on the bridge chip itself but also the panel. In the ps8640 driver, this was made to work by having the bridge chip manually power the panel on by calling pre_enable() on everything connectorward on the bridge chain. This worked OK, but... ...when trying to do the same thing on ti-sn65dsi86, feedback was that this wasn't a great idea. As a result, we designed the "DP AUX" bus. With the design we ended up with the panel driver itself was in charge of reading the EDID. The panel driver could power itself on and the bridge chip was able to power itself on because it implemented the DP AUX bus. Despite the fact that we came up with a new scheme, implemented in on ti-sn65dsi86, and even implemented it on parade-ps8640, we still kept the old code around. This was because the new scheme required a DT change. Previously the panel was a simple "platform_device" and in DT at the top level. With the new design the panel needs to be listed in DT under the DP controller node. The old code allowed us to properly fetch EDIDs with ps8640 with the old DTs. Unfortunately, the old code stopped working as of commit 102e80d1fa2c ("drm/bridge: ps8640: Use atomic variants of drm_bridge_funcs"). There are cases at bootup where connector->state->state is NULL and the kernel crashed at: * drm_atomic_bridge_chain_pre_enable * drm_atomic_get_old_bridge_state * drm_atomic_get_old_private_obj_state The crash went away at commit 4fb912e5e190 ("drm/bridge: Introduce pre_enable_prev_first to alter bridge init order") which added a NULL check. However, even though we were no longer crashing the end result was that we weren't actually powering the panel on when we thought we were. Things could end up working (despite warning splats) if userspace was persistent and tried to get the mode again, but it wasn't great. A bit of digging was done to see if there was an easy fix but there was nothing obvious. Instead, the only device using ps8640 the "old" way had its DT updated so that the panel was no longer a simple "platform_deice". See commit c2d94f72140a ("arm64: dts: mediatek: mt8173-elm: Move display to ps8640 auxiliary bus") and commit 113b5cc06f44 ("arm64: dts: mediatek: mt8173-elm: remove panel model number in DT"). Let's delete the old broken code so nobody gets tempted to copy it or figure out how it works (since it doesn't). NOTE: from a device tree "purist" point of view, we're supposed to keep old device trees working and this patch is technically "against policy". Reasons I'm still proposing it anyway: 1. Officially, old mt8173-elm device trees worked via the "little white lie" approach. The DT would list an arbitrary/representative panel that would be used for power sequencing. The mode information in the panel driver would then be ignored / overridden by the EDID reading code in ps8640. I don't feel too terrible breaking DTs that contained the wrong "compatible" string to begin with. NOTE that any old device trees that _didn't_ lie about their compatible will still work because the mode information will come from the hardcoded panels in panel-edp. 2. The only users of the old code were Chromebooks and Chromebooks don't bake their DTs into the BIOS (they are bundled with the kernel). Thus we don't need to worry about breaking someone using an old DT with a new kernel. 3. The old code was broken anyway. If someone wants to fix the old code instead of deleting it then they have my blessing, but without a proper fix the old code isn't useful. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> --- Changes in v2: - Removed "Fixes" tag as per discussion on v1. - Adjusted commit message since commit 4fb912e5e190 made things not crash. drivers/gpu/drm/bridge/parade-ps8640.c | 79 -------------------------- 1 file changed, 79 deletions(-)