drm/apple: set an external mode again once the display is on

drivers/gpu/drm/apple/iomfb_v14_7.c

@@ -3271,6 +3271,17 @@ static int dcp_v14_external_modeset(struct apple_dcp *dcp, struct drm_crtc_state
 		ret = dcp_v14_set_mode(v14, mode.color_mode_id, mode.timing_mode_id);
 	if (!ret)
 		ret = dcp_v14_set_power(v14, true);
+	/*
+	 * The mode was set with the pipe off. A mode that needs DSC is then
+	 * reset again ("pipe not enabled"), and the power-on only configures
+	 * DSC: the firmware starts the timings in a mode set of its own, after
+	 * the hotplug notification it sends itself, and drops a swap that
+	 * reaches it before then without completing it, so A407 times out.
+	 * Setting the mode once more with the pipe on starts the timings
+	 * before the first swap.
+	 */
+	if (!ret)
+		ret = dcp_v14_set_mode(v14, mode.color_mode_id, mode.timing_mode_id);
 	if (!ret) {
 		v14->panel_width = mode.mode.hdisplay;
 		v14->panel_height = mode.mode.vdisplay;
@@ -3383,6 +3394,7 @@ void iomfb_v14_7_poweroff(struct apple_dcp *dcp)
 
 #if IS_ENABLED(CONFIG_DRM_APPLE_DISPLAY_KUNIT_TEST)
 #include "iomfb_v14_7_external_audio_test.c"
+#include "iomfb_v14_7_external_modeset_test.c"
 #include "iomfb_v14_7_backlight_test.c"
 #include "iomfb_v14_7_backlight_lifetime_test.c"
 #endif

drivers/gpu/drm/apple/iomfb_v14_7_external_modeset_test.c

@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * The DCP calls of an external mode set, included at the end of
+ * iomfb_v14_7.c so that the production dcp_v14_external_modeset() runs.
+ * Every call is answered as accepted; the audio service is stubbed.
+ */
+#include <kunit/device.h>
+#include <kunit/static_stub.h>
+#include <kunit/test.h>
+
+#define V14_EXT_MODESET_MAX_CALLS 8
+
+struct v14_ext_modeset {
+	struct apple_dcp *dcp;
+	struct apple_dcp_v14 *v14;
+	struct dcp_display_mode mode;
+	u32 tags[V14_EXT_MODESET_MAX_CALLS];
+	bool power[V14_EXT_MODESET_MAX_CALLS];
+	unsigned int calls;
+};
+
+static struct v14_ext_modeset *v14_ext_modeset_current;
+
+static int v14_ext_modeset_call(struct apple_dcp_v14 *v14, u32 tag, const void *in, u32 in_size,
+				void *out, u32 out_size, u32 completion, dcp_v14_admit_fn admit,
+				void *admit_cookie)
+{
+	struct v14_ext_modeset *s = v14_ext_modeset_current;
+
+	if (s->calls < V14_EXT_MODESET_MAX_CALLS) {
+		s->tags[s->calls] = tag;
+		s->power[s->calls] = tag == A(472) && in_size >= 8 && get_unaligned_le64(in);
+	}
+	s->calls++;
+	if (out)
+		memset(out, 0, out_size);
+	return 0;
+}
+
+static void v14_ext_modeset_audio(struct apple_dcp *dcp)
+{
+}
+
+static void v14_ext_modeset_retry(struct work_struct *work)
+{
+}
+
+static void v14_ext_modeset_stop(void *data)
+{
+	struct apple_dcp *dcp = data;
+
+	cancel_delayed_work_sync(&dcp->external_retry_wq);
+}
+
+/* A started, described native external session with one mode, its display @powered. */
+static struct v14_ext_modeset *v14_ext_modeset_setup(struct kunit *test, bool powered)
+{
+	struct v14_ext_modeset *s = kunit_kzalloc(test, sizeof(*s), GFP_KERNEL);
+	struct device *dev;
+
+	KUNIT_ASSERT_NOT_NULL(test, s);
+	dev = kunit_device_register(test, "dcp-v14-ext-modeset");
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
+	s->dcp = devm_kzalloc(dev, sizeof(*s->dcp), GFP_KERNEL);
+	s->v14 = devm_kzalloc(dev, sizeof(*s->v14), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, s->dcp);
+	KUNIT_ASSERT_NOT_NULL(test, s->v14);
+	s->dcp->dev = dev;
+	s->dcp->fw_compat = DCP_FIRMWARE_V_14_7;
+	s->dcp->external = true;
+	s->dcp->external_native = true;
+	/* Never dereferenced: the audio service is stubbed. */
+	s->dcp->avep = (struct apple_dcp_afkep *)s;
+	mutex_init(&s->dcp->modes_lock);
+	mutex_init(&s->dcp->hpd_mutex);
+	spin_lock_init(&s->dcp->metadata.lock);
+	spin_lock_init(&s->dcp->mode_state.lock);
+	INIT_DELAYED_WORK(&s->dcp->external_retry_wq, v14_ext_modeset_retry);
+	/* 3840x2160 at 100 Hz, timing 167 and color 219 as a J514S TV reports it. */
+	s->mode.mode = (struct drm_display_mode){
+		DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 1188000, 3840, 4896, 4984, 5280, 0,
+			 2160, 2168, 2178, 2250, 0, DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC)
+	};
+	s->mode.timing_mode_id = 167;
+	s->mode.color_mode_id = 219;
+	s->dcp->modes = &s->mode;
+	s->dcp->nr_modes = 1;
+	s->dcp->modes_admitted = true;
+	s->dcp->v14 = s->v14;
+	s->v14->dev = dev;
+	s->v14->dcp = s->dcp;
+	s->v14->external = true;
+	s->v14->started = true;
+	s->v14->opened = true;
+	s->v14->powered = powered;
+	s->v14->described = DCP_V14_DESC_ALL;
+	mutex_init(&s->v14->lock);
+	init_waitqueue_head(&s->v14->described_wait);
+	KUNIT_ASSERT_EQ(test, kunit_add_action_or_reset(test, v14_ext_modeset_stop, s->dcp), 0);
+	v14_ext_modeset_current = s;
+	kunit_activate_static_stub(test, dcp_v14_call_guarded, v14_ext_modeset_call);
+	kunit_activate_static_stub(test, dcp_v14_audio_off, v14_ext_modeset_audio);
+	kunit_activate_static_stub(test, dcp_v14_audio_on, v14_ext_modeset_audio);
+	return s;
+}
+
+static int v14_ext_modeset_run(struct kunit *test, struct v14_ext_modeset *s)
+{
+	struct drm_crtc_state *state = kunit_kzalloc(test, sizeof(*state), GFP_KERNEL);
+
+	KUNIT_ASSERT_NOT_NULL(test, state);
+	drm_mode_copy(&state->mode, &s->mode.mode);
+	return dcp_v14_external_modeset(s->dcp, state);
+}
+
+/*
+ * A display that was off, as on attach: the mode is set, the display powered
+ * on, and the mode set once more with the pipe on, before any swap. A DSC
+ * mode set with the pipe off only takes effect then.
+ */
+static void v14_ext_modeset_sets_mode_again_after_power_on(struct kunit *test)
+{
+	struct v14_ext_modeset *s = v14_ext_modeset_setup(test, false);
+
+	KUNIT_EXPECT_EQ(test, v14_ext_modeset_run(test, s), 0);
+	KUNIT_ASSERT_EQ(test, s->calls, 3U);
+	KUNIT_EXPECT_EQ(test, s->tags[0], A(411));
+	KUNIT_EXPECT_EQ(test, s->tags[1], A(472));
+	KUNIT_EXPECT_TRUE(test, s->power[1]);
+	KUNIT_EXPECT_EQ(test, s->tags[2], A(411));
+	KUNIT_EXPECT_TRUE(test, s->v14->powered);
+	KUNIT_EXPECT_TRUE(test, s->v14->mode_live);
+	KUNIT_EXPECT_EQ(test, s->v14->mode_timing, 167U);
+	KUNIT_EXPECT_EQ(test, s->v14->mode_color, 219U);
+	KUNIT_EXPECT_FALSE(test, mutex_is_locked(&s->v14->lock));
+}
+
+/* A mode change on a display that is on: power down, set, power up, set again. */
+static void v14_ext_modeset_mode_change(struct kunit *test)
+{
+	struct v14_ext_modeset *s = v14_ext_modeset_setup(test, true);
+
+	KUNIT_EXPECT_EQ(test, v14_ext_modeset_run(test, s), 0);
+	KUNIT_ASSERT_EQ(test, s->calls, 4U);
+	KUNIT_EXPECT_EQ(test, s->tags[0], A(472));
+	KUNIT_EXPECT_FALSE(test, s->power[0]);
+	KUNIT_EXPECT_EQ(test, s->tags[1], A(411));
+	KUNIT_EXPECT_EQ(test, s->tags[2], A(472));
+	KUNIT_EXPECT_TRUE(test, s->power[2]);
+	KUNIT_EXPECT_EQ(test, s->tags[3], A(411));
+	KUNIT_EXPECT_TRUE(test, s->v14->powered);
+}
+
+static struct kunit_case v14_ext_modeset_cases[] = {
+	KUNIT_CASE(v14_ext_modeset_sets_mode_again_after_power_on),
+	KUNIT_CASE(v14_ext_modeset_mode_change),
+	{}
+};
+
+static struct kunit_suite v14_ext_modeset_suite = {
+	.name = "dcp_v14_external_modeset",
+	.test_cases = v14_ext_modeset_cases,
+};
+
+kunit_test_suite(v14_ext_modeset_suite);