diff --git a/libweston/backend-drm/drm.c b/libweston/backend-drm/drm.c
index 46b809be..b55696c9 100644
--- a/libweston/backend-drm/drm.c
+++ b/libweston/backend-drm/drm.c
@@ -1416,10 +1416,10 @@ drm_output_set_gbm_format(struct weston_output *base,
 			  const char *gbm_format)
 {
 	struct drm_output *output = to_drm_output(base);
-	struct drm_backend *b = to_drm_backend(base->compositor);
 
-	if (parse_gbm_format(gbm_format, b->gbm_format, &output->gbm_format) == -1)
-		output->gbm_format = b->gbm_format;
+	if (parse_gbm_format(gbm_format,
+			     DRM_FORMAT_INVALID, &output->gbm_format) == -1)
+		output->gbm_format = DRM_FORMAT_INVALID;
 }
 
 static void
@@ -1855,6 +1855,13 @@ drm_output_enable(struct weston_output *base)
 
 	assert(!output->virtual);
 
+	if (output->gbm_format == DRM_FORMAT_INVALID) {
+		if (output->base.eotf_mode != WESTON_EOTF_MODE_SDR)
+			output->gbm_format = DRM_FORMAT_XRGB2101010;
+		else
+			output->gbm_format = b->gbm_format;
+	}
+
 	ret = drm_output_attach_crtc(output);
 	if (ret < 0)
 		return -1;
@@ -2301,6 +2308,7 @@ drm_output_create(struct weston_compositor *compositor, const char *name)
 	output->backend = b;
 	output->crtc = NULL;
 
+	output->gbm_format = DRM_FORMAT_INVALID;
 #ifdef BUILD_DRM_GBM
 	output->gbm_bo_flags = GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING;
 #endif
diff --git a/man/weston-drm.man b/man/weston-drm.man
index 5947714c..48fd0c8e 100644
--- a/man/weston-drm.man
+++ b/man/weston-drm.man
@@ -57,7 +57,8 @@ The actually supported pixel formats depend on the DRM driver and hardware,
 and the renderer used. Using Pixman-renderer, DRM-backend supports only
 .BR xrgb8888 " and " rgb565 .
 The formats supported with GL-renderer depend on the EGL and OpenGL ES 2 or 3
-implementations. The names are case-insensitive.
+implementations. The names are case-insensitive. This setting applies only to
+.RB "outputs in SDR mode, see " eotf-mode " in " weston.ini (5).
 
 .RB "If not specified, " xrgb8888 " is used. See also " gbm-format " in"
 .BR output " section."
@@ -134,9 +135,11 @@ and possibly flipped. Possible values are
 .TP
 \fBgbm-format\fR=\fIformat\fR
 Set the DRM KMS framebuffer format for this specific output. If not set,
-.RB "the value from " gbm-format " option in " core " section is used."
+.RB "the value from " gbm-format " option in " core " section is used"
+.RB "for SDR mode outputs and " xrgb2101010 " for other modes."
 .RI "For the possible values for " format " see "
 .BR gbm-format " option in " core " section."
+.RB "For SDR mode, see " eotf-mode " in " weston.ini (7).
 .TP
 \fBpixman-shadow\fR=\fIboolean\fR
 If using the Pixman-renderer, use shadow framebuffers. Defaults to