drm/i915: Show bios vbt when read from firmware/spi/oprom

Make debugfs vbt only shows valid vbt when read from ACPI opregion.
Make it work when read from firmware/spi/pci oprom cases. In the cases
where VBT needs to be read from spi/pci oprom, take the wakeref to
prevent WARN while reading DE registers during debugfs vbt dump.

v2: Extract getting vbt from different sources to its own function.
    Protect sysfs write with vbt check(Jani)
v3: Fix CI error by probing bios vbt with runtime_pm wakeref
v4: Update commit message and skip waking up runtime while accessing
    vbt from opregion/firmware(Jani)
v5: Skip grabbing unnecessary wakeref(Jani)

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240304212331.640424-1-radhakrishna.sripada@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 51954deaf64415dc3b4f69f6df26e9bb1debe1a7..c7841b3eede85c98f67fdfeeaea33597efc02401 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -3166,6 +3166,32 @@ err_unmap_oprom:
        return NULL;
 }
 
+static const struct vbt_header *intel_bios_get_vbt(struct drm_i915_private *i915,
+                                                  size_t *sizep)
+{
+       const struct vbt_header *vbt = NULL;
+       intel_wakeref_t wakeref;
+
+       vbt = firmware_get_vbt(i915, sizep);
+
+       if (!vbt)
+               vbt = intel_opregion_get_vbt(i915, sizep);
+
+       /*
+        * If the OpRegion does not have VBT, look in SPI flash
+        * through MMIO or PCI mapping
+        */
+       if (!vbt && IS_DGFX(i915))
+               with_intel_runtime_pm(&i915->runtime_pm, wakeref)
+                       vbt = spi_oprom_get_vbt(i915, sizep);
+
+       if (!vbt)
+               with_intel_runtime_pm(&i915->runtime_pm, wakeref)
+                       vbt = oprom_get_vbt(i915, sizep);
+
+       return vbt;
+}
+
 /**
  * intel_bios_init - find VBT and initialize settings from the BIOS
  * @i915: i915 device instance
@@ -3177,7 +3203,6 @@ err_unmap_oprom:
 void intel_bios_init(struct drm_i915_private *i915)
 {
        const struct vbt_header *vbt;
-       struct vbt_header *oprom_vbt = NULL;
        const struct bdb_header *bdb;
 
        INIT_LIST_HEAD(&i915->display.vbt.display_devices);
@@ -3191,27 +3216,7 @@ void intel_bios_init(struct drm_i915_private *i915)
 
        init_vbt_defaults(i915);
 
-       oprom_vbt = firmware_get_vbt(i915, NULL);
-       vbt = oprom_vbt;
-
-       if (!vbt) {
-               oprom_vbt = intel_opregion_get_vbt(i915, NULL);
-               vbt = oprom_vbt;
-       }
-
-       /*
-        * If the OpRegion does not have VBT, look in SPI flash through MMIO or
-        * PCI mapping
-        */
-       if (!vbt && IS_DGFX(i915)) {
-               oprom_vbt = spi_oprom_get_vbt(i915, NULL);
-               vbt = oprom_vbt;
-       }
-
-       if (!vbt) {
-               oprom_vbt = oprom_get_vbt(i915, NULL);
-               vbt = oprom_vbt;
-       }
+       vbt = intel_bios_get_vbt(i915, NULL);
 
        if (!vbt)
                goto out;
@@ -3244,7 +3249,7 @@ out:
        parse_sdvo_device_mapping(i915);
        parse_ddi_ports(i915);
 
-       kfree(oprom_vbt);
+       kfree(vbt);
 }
 
 static void intel_bios_init_panel(struct drm_i915_private *i915,
@@ -3774,13 +3779,12 @@ static int intel_bios_vbt_show(struct seq_file *m, void *unused)
        const void *vbt;
        size_t vbt_size;
 
-       /*
-        * FIXME: VBT might originate from other places than opregion, and then
-        * this would be incorrect.
-        */
-       vbt = intel_opregion_get_vbt(i915, &vbt_size);
-       if (vbt)
+       vbt = intel_bios_get_vbt(i915, &vbt_size);
+
+       if (vbt) {
                seq_write(m, vbt, vbt_size);
+               kfree(vbt);
+       }
 
        return 0;
 }