On 9/4/2024 12:23 PM, Ville Syrjälä wrote:
On Wed, Sep 04, 2024 at 09:41:23PM +0300, Dmitry Baryshkov wrote:
On Wed, 4 Sept 2024 at 01:18, Jessica Zhang <[email protected]> wrote:
On 8/30/2024 10:00 AM, Dmitry Baryshkov wrote:
On Thu, Aug 29, 2024 at 01:48:28PM GMT, Jessica Zhang wrote:
Check that each encoder in the CRTC state's encoder_mask is marked as a
possible clone for all other encoders in the encoder_mask and that only
one CRTC is in clone mode at a time
Signed-off-by: Jessica Zhang <[email protected]>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 36
+++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 5ec1b5a38922..bebae365c036 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights
reserved.
+ * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights
reserved.
* Copyright (c) 2014-2021 The Linux Foundation. All rights reserved.
* Copyright (C) 2013 Red Hat
* Author: Rob Clark <[email protected]>
@@ -1204,6 +1204,36 @@ static struct msm_display_topology dpu_crtc_get_topology(
return topology;
}
+static bool dpu_crtc_has_valid_clones(struct drm_crtc *crtc,
+ struct drm_crtc_state *crtc_state)
+{
+ struct drm_encoder *drm_enc;
+ struct drm_crtc *temp_crtc;
+ int num_cwb_sessions = 0;
+
+ drm_for_each_crtc(temp_crtc, crtc->dev)
+ if (drm_crtc_in_clone_mode(temp_crtc->state))
No, get the state from drm_atomic_state. temp_crtc->state might be
irrelevant.
Hi Dmitry,
Ack.
+ num_cwb_sessions++;
Even simpler:
if (temp_crtc != crtc && drm_crtc_in_clone_mode(...))
return false;
Ack.
+
+ /*
+ * Only support a single concurrent writeback session running
+ * at a time
If it is not a hardware limitation, please add:
FIXME: support more than one session
This is a hardware limitation.
+ */
+ if (num_cwb_sessions > 1)
+ return false;
+
+ 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) {
Align to opening bracket, please. Granted that other drivers don't
perform this check, is it really necessary? Doesn't
validate_encoder_possible_clones() ensure the same, but during the
encoder registration?
The difference here is that validate_encoder_possible_clones() is only
called when the drm device is initially registered.
The check here is to make sure that the encoders userspace is proposing
to be cloned are actually possible clones of each other. This might not
be necessary for drivers where all encoders are all possible clones of
each other. But for MSM (and CWB), real-time display encoders can only
be clones of writeback (and vice versa).
I had the feeling that encoder_mask should already take care of that,
but it seems I was wrong.
Please extract this piece as a generic helper. I think it should be
called from the generic atomic_check() codepath.
Yeah, if we are semi-assured that drivers aren't screwing up those
bitmasks anymore we could shove the cloning checks into
drm_atomic_helper_check_modeset(). It already checks possible_crtcs.
We could then throw out the equavalent code from i915 as well...
Hi Ville and Dmitry,
Sure, I can move this part of the check to *_atomic_check_modeset() --
I'll add it here [1] since it's after the encoder mask is updated.
[1]
https://elixir.bootlin.com/linux/v6.10.7/source/drivers/gpu/drm/drm_atomic_helper.c#L731
Are there decent IGTs to make sure the kernel properly rejects
illegal cloning configurations?
There's a few invalid clone subtests in kms_setmode [2]
Thanks,
Jessica Zhang
[2]
https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/kms_setmode.c#L63
--
Ville Syrjälä
Intel
