[PATCH] drm: Use EOPNOTSUPP, not ENOTSUPP

[Daniel Vetter]

- it's what we recommend in our docs:

https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#recommended-ioctl-return-values

- it's the overwhelmingly used error code for "operation not
  supported", at least in drm core (slightly less so in drivers):

$ git grep EOPNOTSUP -- drivers/gpu/drm/*c | wc -l
83
$ git grep ENOTSUP -- drivers/gpu/drm/*c | wc -l
5

- include/linux/errno.h makes it fairly clear that these are for nfsv3
  (plus they also have error codes above 512, which is the block with
  some special behaviour ...)

/* Defined for the NFSv3 protocol */

If the above isn't reflecting current practice, then I guess we should
at least update the docs.

Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Sean Paul <sean at poorly.run>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Andres Rodriguez <andresx7 at gmail.com>
Cc: Noralf Trønnes <noralf at tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_edid.c     | 6 +++---
 drivers/gpu/drm/drm_mipi_dbi.c | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 82a4ceed3fcf..12c783f4d956 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3719,7 +3719,7 @@ cea_db_offsets(const u8 *cea, int *start, int *end)
 		if (*end < 4 || *end > 127)
 			return -ERANGE;
 	} else {
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 	}
 
 	return 0;
@@ -4188,7 +4188,7 @@ int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads)
 
 	if (cea_revision(cea) < 3) {
 		DRM_DEBUG_KMS("SAD: wrong CEA revision\n");
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 	}
 
 	if (cea_db_offsets(cea, &start, &end)) {
@@ -4249,7 +4249,7 @@ int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)
 
 	if (cea_revision(cea) < 3) {
 		DRM_DEBUG_KMS("SAD: wrong CEA revision\n");
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 	}
 
 	if (cea_db_offsets(cea, &start, &end)) {
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index c4ee2709a6f3..f8154316a3b0 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -955,7 +955,7 @@ static int mipi_dbi_typec1_command(struct mipi_dbi *dbi, u8 *cmd,
 	int ret;
 
 	if (mipi_dbi_command_is_read(dbi, *cmd))
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 
 	MIPI_DBI_DEBUG_COMMAND(*cmd, parameters, num);
 
-- 
2.23.0