[Intel-gfx] [RESEND] drm/edid/firmware: stop using a throwaway platform device

[Jani Nikula <jani.nikula@intel.com>]

We've used a temporary platform device for firmware EDID loading since
it was introduced in commit da0df92b5731 ("drm: allow loading an EDID as
firmware to override broken monitor"), but there's no explanation why.

Using a temporary device does not play well with CONFIG_FW_CACHE=y,
which caches firmware images (e.g. on suspend) so that drivers can
request firmware when the system is not ready for it, and return the
images from the cache (e.g. during resume). This works automatically for
regular devices, but obviously not for a temporarily created device.

Stop using the throwaway platform device, and use the drm device
instead.

Note that this may still be problematic for cases where the display was
plugged in during suspend, and the firmware wasn't loaded and therefore
not cached before suspend.

References: https://lore.kernel.org/r/20220727074152.43059-1-matthieu.charette@gmail.com
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2061
Reported-by: Matthieu CHARETTE <matthieu.charette@gmail.com>
Tested-by: Matthieu CHARETTE <matthieu.charette@gmail.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

---

Resend with a proper commit message; patch itself is unchanged.
---
 drivers/gpu/drm/drm_edid_load.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
index ef4ab59d6935..5d9ef267ebb3 100644
--- a/drivers/gpu/drm/drm_edid_load.c
+++ b/drivers/gpu/drm/drm_edid_load.c
@@ -172,20 +172,9 @@ static const struct drm_edid *edid_load(struct drm_connector *connector, const c
 		fwdata = generic_edid[builtin];
 		fwsize = sizeof(generic_edid[builtin]);
 	} else {
-		struct platform_device *pdev;
 		int err;
 
-		pdev = platform_device_register_simple(connector->name, -1, NULL, 0);
-		if (IS_ERR(pdev)) {
-			drm_err(connector->dev,
-				"[CONNECTOR:%d:%s] Failed to register EDID firmware platform device for connector \"%s\"\n",
-				connector->base.id, connector->name,
-				connector->name);
-			return ERR_CAST(pdev);
-		}
-
-		err = request_firmware(&fw, name, &pdev->dev);
-		platform_device_unregister(pdev);
+		err = request_firmware(&fw, name, connector->dev->dev);
 		if (err) {
 			drm_err(connector->dev,
 				"[CONNECTOR:%d:%s] Requesting EDID firmware \"%s\" failed (err=%d)\n",
-- 
2.34.1