From: jsg <jsg@openbsd.org>
Date: Thu, 15 Jun 2023 02:44:18 +0000 (+0000)
Subject: drm/i915: Expand force_probe to block probe of devices as well.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=db1b00f2cabea7942c838d030d7b2a501e8eb896;p=openbsd

drm/i915: Expand force_probe to block probe of devices as well.

From Rodrigo Vivi
36fa6187753a9b52f2bbf2f3ba628f6bad314510 in linux-6.1.y/6.1.30
157821fb3e9aaa07cf408686b08d117bf27b7de1 in mainline linux
---

diff --git a/sys/dev/pci/drm/i915/i915_params.c b/sys/dev/pci/drm/i915/i915_params.c
index d1e4d528cb1..5b24dd50fb6 100644
--- a/sys/dev/pci/drm/i915/i915_params.c
+++ b/sys/dev/pci/drm/i915/i915_params.c
@@ -122,7 +122,7 @@ i915_param_named_unsafe(enable_psr2_sel_fetch, bool, 0400,
 	"Default: 0");
 
 i915_param_named_unsafe(force_probe, charp, 0400,
-	"Force probe the driver for specified devices. "
+	"Force probe options for specified supported devices. "
 	"See CONFIG_DRM_I915_FORCE_PROBE for details.");
 
 i915_param_named_unsafe(disable_power_well, int, 0400,
diff --git a/sys/dev/pci/drm/i915/i915_pci.c b/sys/dev/pci/drm/i915/i915_pci.c
index 6dedad54a92..ef72617b105 100644
--- a/sys/dev/pci/drm/i915/i915_pci.c
+++ b/sys/dev/pci/drm/i915/i915_pci.c
@@ -1253,7 +1253,7 @@ static void i915_pci_remove(struct pci_dev *pdev)
 }
 
 /* is device_id present in comma separated list of ids */
-static bool force_probe(u16 device_id, const char *devices)
+static bool device_id_in_list(u16 device_id, const char *devices, bool negative)
 {
 	char *s, *p, *tok;
 	bool ret;
@@ -1262,7 +1262,9 @@ static bool force_probe(u16 device_id, const char *devices)
 		return false;
 
 	/* match everything */
-	if (strcmp(devices, "*") == 0)
+	if (negative && strcmp(devices, "!*") == 0)
+		return true;
+	if (!negative && strcmp(devices, "*") == 0)
 		return true;
 
 	s = kstrdup(devices, GFP_KERNEL);
@@ -1272,6 +1274,12 @@ static bool force_probe(u16 device_id, const char *devices)
 	for (p = s, ret = false; (tok = strsep(&p, ",")) != NULL; ) {
 		u16 val;
 
+		if (negative && tok[0] == '!')
+			tok++;
+		else if ((negative && tok[0] != '!') ||
+			 (!negative && tok[0] == '!'))
+			continue;
+
 		if (kstrtou16(tok, 16, &val) == 0 && val == device_id) {
 			ret = true;
 			break;
@@ -1283,6 +1291,16 @@ static bool force_probe(u16 device_id, const char *devices)
 	return ret;
 }
 
+static bool id_forced(u16 device_id)
+{
+	return device_id_in_list(device_id, i915_modparams.force_probe, false);
+}
+
+static bool id_blocked(u16 device_id)
+{
+	return device_id_in_list(device_id, i915_modparams.force_probe, true);
+}
+
 bool i915_pci_resource_valid(struct pci_dev *pdev, int bar)
 {
 	if (!pci_resource_flags(pdev, bar))
@@ -1310,10 +1328,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		(struct intel_device_info *) ent->driver_data;
 	int err;
 
-	if (intel_info->require_force_probe &&
-	    !force_probe(pdev->device, i915_modparams.force_probe)) {
+	if (intel_info->require_force_probe && !id_forced(pdev->device)) {
 		dev_info(&pdev->dev,
-			 "Your graphics device %04x is not properly supported by the driver in this\n"
+			 "Your graphics device %04x is not properly supported by i915 in this\n"
 			 "kernel version. To force driver probe anyway, use i915.force_probe=%04x\n"
 			 "module parameter or CONFIG_DRM_I915_FORCE_PROBE=%04x configuration option,\n"
 			 "or (recommended) check for kernel updates.\n",
@@ -1321,6 +1338,12 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return -ENODEV;
 	}
 
+	if (id_blocked(pdev->device)) {
+		dev_info(&pdev->dev, "I915 probe blocked for Device ID %04x.\n",
+			 pdev->device);
+		return -ENODEV;
+	}
+
 	/* Only bind to function 0 of the device. Early generations
 	 * used function 1 as a placeholder for multi-head. This causes
 	 * us confusion instead, especially on the systems where both