linux-kernel - Re: [PATCH 10/10] drm/tidss: Fix atomic

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Message-ID: <ZUO4f/OjdYW4Paxu@francesco-nb.int.toradex.com>
Date:   Thu, 2 Nov 2023 15:55:59 +0100
From:   Francesco Dolcini <francesco@...cini.it>
To:     Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc:     Aradhya Bhatia <a-bhatia1@...com>,
        Devarsh Thakkar <devarsht@...com>,
        Jyri Sarha <jyri.sarha@....fi>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH 10/10] drm/tidss: Fix atomic_flush check

On Wed, Nov 01, 2023 at 11:17:47AM +0200, Tomi Valkeinen wrote:
> tidss_crtc_atomic_flush() checks if the crtc is enabled, and if not,
> returns immediately as there's no reason to do any register changes.
> 
> However, the code checks for 'crtc->state->enable', which does not
> reflect the actual HW state. We should instead look at the
> 'crtc->state->active' flag.
> 
> This causes the tidss_crtc_atomic_flush() to proceed with the flush even
> if the active state is false, which then causes us to hit the
> WARN_ON(!crtc->state->event) check.
> 
> Fix this by checking the active flag, and while at it, fix the related
> debug print which had "active" and "needs modeset" wrong way.

Candidate for stable? Add a Fixes tag?

Francesco