Re: [PATCH v2 02/22] drm: Add valid clones check
From: Jessica Zhang
Date: Mon Dec 16 2024 - 14:47:41 EST
On 12/16/2024 6:47 AM, Maxime Ripard wrote:
On Fri, Dec 06, 2024 at 04:48:43PM -0800, Jessica Zhang wrote:
On 9/25/2024 12:23 AM, Maxime Ripard wrote:
On Tue, Sep 24, 2024 at 03:59:18PM GMT, Jessica Zhang wrote:
Check that all encoders attached to a given CRTC are valid
possible_clones of each other.
Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
---
drivers/gpu/drm/drm_atomic_helper.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 43cdf39019a4..cc4001804fdc 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -574,6 +574,25 @@ mode_valid(struct drm_atomic_state *state)
return 0;
}
+static int drm_atomic_check_valid_clones(struct drm_atomic_state *state,
+ struct drm_crtc *crtc)
+{
+ struct drm_encoder *drm_enc;
+ struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
+ crtc);
+
+ drm_for_each_encoder_mask(drm_enc, crtc->dev, crtc_state->encoder_mask) {
+ if ((crtc_state->encoder_mask & drm_enc->possible_clones) !=
+ crtc_state->encoder_mask) {
+ DRM_DEBUG("crtc%d failed valid clone check for mask 0x%x\n",
+ crtc->base.id, crtc_state->encoder_mask);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
/**
* drm_atomic_helper_check_modeset - validate state object for modeset changes
* @dev: DRM device
@@ -745,6 +764,10 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
ret = drm_atomic_add_affected_planes(state, crtc);
if (ret != 0)
return ret;
+
+ ret = drm_atomic_check_valid_clones(state, crtc);
+ if (ret != 0)
+ return ret;
}
Pretty much the same comment, we should have kunit tests for this.
Hey Maxime,
I'm working on the kunit test for this and had a question on the design for
the unit test:
Since this is a static helper that returns a pretty common error code, how
would you recommend going about making sure that
`drm_atomic_check_valid_clones()` specifically is returning the error (and
not a different part of check_modeset) when testing the check_valid_clones()
failure path?
There's two ways to go about it. Either you can unit test it, prepare a
series of custom states and use
EXPORT_SYMBOL_FOR_TESTS_ONLY/EXPORT_SYMBOL_IF_KUNIT, or you can go the
integration test way and just test that drm_atomic_check is rejected for
unsafe combinations.
I guess I'd prefer the former, but the latter also makes sense and
eventually, it checks what we want: to make sure that we reject such a
state. What part of the code does or with what error code is less
important imo.
Thanks for confirming! The changes I made are based on the latter
approach. Will post the changes later today if you have no objections on
this
Thanks,
Jessica Zhang
Maxime