From: Boris Brezillon <bbrezillon@kernel.org>
To: Peter Rosin <peda@axentia.se>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
David Airlie <airlied@linux.ie>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
Boris Brezillon <boris.brezillon@bootlin.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame
Date: Thu, 10 Jan 2019 18:29:17 +0100 [thread overview]
Message-ID: <20190110182904.5efd08f2@bbrezillon> (raw)
In-Reply-To: <20190110151020.30468-5-peda@axentia.se>
On Thu, 10 Jan 2019 15:10:48 +0000
Peter Rosin <peda@axentia.se> wrote:
> The A2Q and UPDATE bits have no effect in the channel disable registers.
> However, since they are present, assume that the intention is to disable
> planes, not immediately as indicated by the RST bit, but on the next
> frame shift since that is what A2Q and UPDATE means in the channel enable
> registers.
>
> Disabling the plane on the next frame shift is done with the EN bit,
> so use that.
It's been a long time, but I think I had a good reason for forcing a
reset. IIRC, when you don't do that and the CRTC is disabled before the
plane, the EN bit stays around, and next time you queue a plane update,
you'll start with an invalid buf pointer.
>
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
> drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> index 05519e8c6586..f2f570642f84 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c
> @@ -728,9 +728,7 @@ static void atmel_hlcdc_plane_atomic_disable(struct drm_plane *p,
>
> /* Disable the layer */
> atmel_hlcdc_layer_write_reg(&plane->layer, ATMEL_HLCDC_LAYER_CHDR,
> - ATMEL_HLCDC_LAYER_RST |
> - ATMEL_HLCDC_LAYER_A2Q |
> - ATMEL_HLCDC_LAYER_UPDATE);
> + ATMEL_HLCDC_LAYER_EN);
>
> /* Clear all pending interrupts */
> atmel_hlcdc_layer_read_reg(&plane->layer, ATMEL_HLCDC_LAYER_ISR);
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next prev parent reply other threads:[~2019-01-10 17:30 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 15:10 [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Peter Rosin
2019-01-10 15:10 ` [PATCH 1/4] drm/atmel-hlcdc: rotate planes counterclockwise Peter Rosin
2019-01-10 15:10 ` [PATCH 2/4] drm/atmel-hlcdc: do not swap w/h of the crtc when a plane is rotated Peter Rosin
2019-01-10 17:48 ` Boris Brezillon
2019-01-11 13:29 ` Peter Rosin
2019-01-11 14:14 ` Nicolas.Ferre
2019-01-10 15:10 ` [PATCH 3/4] drm/atmel-hlcdc: fix clipping of planes Peter Rosin
2019-01-10 15:10 ` [PATCH 4/4] drm/atmel-hlcdc: do not immediately disable planes, wait for next frame Peter Rosin
2019-01-10 17:29 ` Boris Brezillon [this message]
2019-01-10 18:51 ` Peter Rosin
2019-01-10 19:25 ` Boris Brezillon
2019-01-11 14:29 ` Peter Rosin
2019-01-16 14:45 ` Boris Brezillon
2019-01-10 17:45 ` [PATCH 0/4] drm/atmel-hlcdc: fix plane clipping/rotation issues Boris Brezillon
2019-01-10 20:16 ` Sam Ravnborg
2019-01-11 9:16 ` Peter Rosin
2019-01-10 21:24 ` Peter Rosin
2019-01-11 14:18 ` Nicolas.Ferre
2019-01-27 8:27 ` Boris Brezillon
2019-01-31 13:13 ` Peter Rosin
2019-01-31 13:21 ` Boris Brezillon
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