drm/apple: reject unimplemented external H17P VRR

MAINTAINERS

@@ -1952,6 +1952,7 @@ L:	dri-devel@lists.freedesktop.org
 S:	Maintained
 T:	git git://anongit.freedesktop.org/drm/drm-misc
 F:	drivers/gpu/drm/apple/
+F:	tools/diagnostics/test-apple-external-vrr.py
 F:	tools/testing/selftests/drivers/gpu/apple-afkv2/
 
 APPLE PCIE CONTROLLER DRIVER

drivers/gpu/drm/apple/dcp.c

@@ -2334,6 +2334,12 @@ int dcp_crtc_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
 
 	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
+	/* External H17P does not program adaptive sync. */
+	if (dcp->hw.iomfb_method_profile ==
+	    DCP_IOMFB_METHODS_H17P_EXTERNAL_EXPERIMENTAL &&
+	    crtc_state->vrr_enabled)
+		return -EINVAL;
+
 	needs_modeset = drm_atomic_crtc_needs_modeset(crtc_state) ||
 			!READ_ONCE(dcp->mode_state.valid);
 	if (!needs_modeset && (!dcp->connector || !dcp->connector->connected)) {

drivers/gpu/drm/apple/parser.c

@@ -765,8 +765,12 @@ static int parse_mode(struct dcp_parse_ctx *handle,
 		out->vrr = true;
 	}
 
-	/* Refresh rates are reported by DCP as 16.16 fixed-point Hz. */
-	if (min_vrr && max_vrr > min_vrr) {
+	/*
+	 * Refresh rates are reported by DCP as 16.16 fixed-point Hz.
+	 * External H17P skips adaptive-sync programming: keep the fixed timing
+	 * available, but do not advertise its sink VRR range as driver support.
+	 */
+	if (!external_sdr && min_vrr && max_vrr > min_vrr) {
 		out->min_vrr = min_vrr;
 		out->max_vrr = max_vrr;
 		out->vrr = true;

tools/diagnostics/test-apple-external-sdr.py

@@ -74,10 +74,10 @@ def timing(colors, rate=60, identity=203, score=10):
 
 cases = []
 
-def case(name, timings, external=True, count=1, identity=9, depth=8, clock=148500):
+def case(name, timings, external=True, count=1, identity=9, depth=8, clock=148500, vrr=False):
     out = bytearray(struct.pack('<I', 0xd3))
     wire(timings, out)
-    cases.append((name, bytes(out), external, count, identity, depth, clock))
+    cases.append((name, bytes(out), external, count, identity, depth, clock, vrr))
 
 
 wide = color(84, 1000, Colorimetry=9, Depth=10)
@@ -91,7 +91,13 @@ def case(name, timings, external=True, count=1, identity=9, depth=8, clock=14850
 case('default fallback retains firmware ID', [timing([color(123456, 4, Colorimetry=16)])], identity=123456)
 case('ties preserve firmware order', [timing([srgb, color(12, 10, Colorimetry=1)])])
 case('360Hz is not filtered by color policy', [timing([wide, srgb], rate=360)], clock=891000)
-case('VRR-compatible high refresh color', [dict(timing([srgb], rate=240), MinimumVariableRefreshRate=48 << 16, MaximumVariableRefreshRate=240 << 16)], clock=594000)
+adaptive = dict(timing([srgb], rate=240), MinimumVariableRefreshRate=48 << 16,
+                MaximumVariableRefreshRate=240 << 16)
+case('external VRR sink retains fixed high refresh', [adaptive], clock=594000)
+case('legacy VRR remains available', [adaptive], False, clock=594000, vrr=True)
+case('internal VRR remains available', [adaptive], False, clock=594000, vrr=True)
+case('internal ProMotion fallback remains available', [timing([srgb], rate=120)],
+     False, clock=297000, vrr=True)
 for name, changes in [
     ('BT2020 RGB', dict(Colorimetry=9)), ('BT2020 YCC', dict(Colorimetry=7)),
     ('BT2020 cYCC', dict(Colorimetry=6)), ('P3 D65', dict(Colorimetry=14)),
@@ -220,7 +226,7 @@ def restricted(rate=60, unsafe=None, dsc=None, colors=None, before=False):
 int main(void)
 {
 '''
-for i, (name, blob, external, count, identity, depth, clock) in enumerate(cases):
+for i, (name, blob, external, count, identity, depth, clock, vrr) in enumerate(cases):
     suffix += f'''
     {{
         struct dcp_parse_ctx ctx;
@@ -238,6 +244,7 @@ def restricted(rate=60, unsafe=None, dsc=None, colors=None, before=False):
         assert(modes[0].color_mode_id == {identity});
         assert(modes[0].sdr_rgb.depth == {depth});
         assert(modes[0].mode.clock == {clock});
+        assert(modes[0].vrr == {str(vrr).lower()});
         assert(modes[0].mode.type & DRM_MODE_TYPE_PREFERRED);
 '''
     suffix += '        free(modes);\n    }\n'

tools/diagnostics/test-apple-external-vrr.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+"""Exercise the production atomic admission check for external H17P VRR."""
+from pathlib import Path
+import os
+import shlex
+import subprocess
+import tempfile
+
+root = Path(__file__).resolve().parents[2]
+source = (root / 'drivers/gpu/drm/apple/dcp.c').read_text()
+start = source.index('int dcp_crtc_atomic_check(')
+opening = source.index('{', start)
+end, depth = opening + 1, 1
+while depth:
+    depth += (source[end] == '{') - (source[end] == '}')
+    end += 1
+check = source[start:end]
+prefix = r"""
+#undef NDEBUG
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <errno.h>
+#define DCP_IOMFB_METHODS_H17P_EXTERNAL_EXPERIMENTAL 2
+#define READ_ONCE(x) (x)
+#define dev_dbg(...) ((void)0)
+struct apple_connector { bool connected; };
+struct apple_dcp {
+    bool crashed;
+    struct { int iomfb_method_profile; } hw;
+    struct { bool valid; } mode_state;
+    struct apple_connector *connector;
+    void *dev;
+};
+struct platform_device { struct apple_dcp *data; };
+struct drm_crtc { struct platform_device *dcp; };
+struct drm_crtc_state { bool vrr_enabled, modeset; };
+struct drm_atomic_state { struct drm_crtc_state crtc; };
+#define to_apple_crtc(x) (x)
+#define platform_get_drvdata(x) ((x)->data)
+static struct drm_crtc_state *drm_atomic_get_new_crtc_state(
+    struct drm_atomic_state *s, struct drm_crtc *c)
+{ (void)c; return &s->crtc; }
+static bool drm_atomic_crtc_needs_modeset(struct drm_crtc_state *s)
+{ return s->modeset; }
+"""
+suffix = r"""
+int main(void)
+{
+    struct apple_connector connector = { .connected = true };
+    struct apple_dcp dcp = { .connector = &connector };
+    struct platform_device pdev = { .data = &dcp };
+    struct drm_crtc crtc = { .dcp = &pdev };
+    struct drm_atomic_state state = {0};
+    unsigned int cases = 0;
+    /* Check initial modesets, plane-only commits and link recovery states. */
+    for (unsigned int profile = 0; profile < 3; profile++)
+    for (unsigned int valid = 0; valid < 2; valid++)
+    for (unsigned int modeset = 0; modeset < 2; modeset++)
+    for (unsigned int link = 0; link < 3; link++)
+    for (unsigned int vrr = 0; vrr < 2; vrr++) {
+        dcp.hw.iomfb_method_profile = profile;
+        dcp.mode_state.valid = valid;
+        state.crtc.modeset = modeset;
+        state.crtc.vrr_enabled = vrr;
+        dcp.connector = link == 2 ? NULL : &connector;
+        connector.connected = link == 1;
+        int expected = profile == DCP_IOMFB_METHODS_H17P_EXTERNAL_EXPERIMENTAL && vrr ? -EINVAL : 0;
+        int actual = dcp_crtc_atomic_check(&crtc, &state);
+        if (actual != expected) {
+            fprintf(stderr, "profile=%u valid=%u modeset=%u link=%u vrr=%u: got %d expected %d\n",
+                    profile, valid, modeset, link, vrr, actual, expected);
+            return 1;
+        }
+        cases++;
+    }
+    dcp.crashed = true;
+    state.crtc.vrr_enabled = false;
+    assert(dcp_crtc_atomic_check(&crtc, &state) == -EINVAL);
+    printf("PASS: %u production atomic VRR admission cases and crashed-device rejection\n", cases);
+    return 0;
+}
+"""
+with tempfile.TemporaryDirectory(prefix='apple-external-vrr-') as tmp:
+    tmp = Path(tmp)
+    unit = tmp / 'test.c'
+    unit.write_text(prefix + check + suffix)
+    command = shlex.split(os.environ.get('CC', 'clang'))
+    command += ['-std=gnu11', '-Wall', '-Wextra', '-Werror', '-O1', '-g',
+                '-fsanitize=address,undefined', '-fno-omit-frame-pointer']
+    subprocess.run(command + [str(unit), '-o', str(tmp / 'test')], check=True)
+    subprocess.run([str(tmp / 'test')], check=True)