Re: [PATCH 5/6] drm: vkms: Prepare `vkms_wb_encoder_atomic_check` to accept multiple formats

From: Igor Matheus Andrade Torrente
Date: Mon Oct 18 2021 - 13:41:55 EST


Hello,

On 10/18/21 7:14 AM, Thomas Zimmermann wrote:
Hi

Am 05.10.21 um 22:16 schrieb Igor Matheus Andrade Torrente:
Currently, the vkms atomic check only goes through the first position of
the `vkms_wb_formats` vector.

This change prepares the atomic_check to check the entire vector.

Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@xxxxxxxxx>
---
  drivers/gpu/drm/vkms/vkms_writeback.c | 11 ++++++++++-
  1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
index 5a3e12f105dc..56978f499203 100644
--- a/drivers/gpu/drm/vkms/vkms_writeback.c
+++ b/drivers/gpu/drm/vkms/vkms_writeback.c
@@ -30,6 +30,8 @@ static int vkms_wb_encoder_atomic_check(struct drm_encoder *encoder,
  {
      struct drm_framebuffer *fb;
      const struct drm_display_mode *mode = &crtc_state->mode;
+    bool format_supported = false;
+    int i;
      if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
          return 0;
@@ -41,7 +43,14 @@ static int vkms_wb_encoder_atomic_check(struct drm_encoder *encoder,
          return -EINVAL;
      }
-    if (fb->format->format != vkms_wb_formats[0]) {
+    for (i = 0; i < ARRAY_SIZE(vkms_wb_formats); i++) {
+        if (fb->format->format == vkms_wb_formats[i]) {
+            format_supported = true;
+            break;
+        }
+    }

At a minimum, this loop should be in a helper function. But more generally, I'm surprised that this isn't already covered by the DRM's atomic helpers.

Ok, I can wrap it in a new function.

AFAIK the DRM doesn't cover it. But I may be wrong...


Best regards
Thomas

+
+    if (!format_supported) {
          DRM_DEBUG_KMS("Invalid pixel format %p4cc\n",
                    &fb->format->format);
          return -EINVAL;