From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> To: dri-devel@lists.freedesktop.org Cc: linux-sh@vger.kernel.org Subject: [PATCH 2/2] drm: rcar-du: Disable all planes when stopping the CRTC Date: Thu, 14 May 2015 12:34:02 +0000 [thread overview] Message-ID: <1431606842-15522-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com> (raw) In-Reply-To: <1431606842-15522-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> The DSnPR plane configuration registers are updated on vblank, and no vblank will occur once the CRTC is stopped. We thus can't only disable planes right before starting the CRTC as it would start scanning out immediately from old frame buffers until the next vblank. Fix the problem by disabling all planes when stopping the CRTC and wait for the change to take effect. This increases the CRTC stop delay, especially when multiple CRTCs are stopped in one operation as we now wait for one vblank per CRTC. Whether this can be improved needs to be researched. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> --- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index e6a32c4e4040..a40085806f5b 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c @@ -398,6 +398,19 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc) if (!rcrtc->started) return; + /* Disable all planes and wait for the change to take effect. This is + * required as the DSnPR registers are updated on vblank, and no vblank + * will occur once the CRTC is stopped. Disabling planes when starting + * the CRTC thus wouldn't be enough as it would start scanning out + * immediately from old frame buffers until the next vblank. + * + * This increases the CRTC stop delay, especially when multiple CRTCs + * are stopped in one operation as we now wait for one vblank per CRTC. + * Whether this can be improved needs to be researched. + */ + rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0); + drm_crtc_wait_one_vblank(crtc); + /* Disable vertical blanking interrupt reporting. We first need to wait * for page flip completion before stopping the CRTC as userspace * expects page flips to eventually complete. -- Regards, Laurent Pinchart
WARNING: multiple messages have this Message-ID (diff)
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> To: dri-devel@lists.freedesktop.org Cc: linux-sh@vger.kernel.org Subject: [PATCH 2/2] drm: rcar-du: Disable all planes when stopping the CRTC Date: Thu, 14 May 2015 15:34:02 +0300 [thread overview] Message-ID: <1431606842-15522-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com> (raw) In-Reply-To: <1431606842-15522-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> The DSnPR plane configuration registers are updated on vblank, and no vblank will occur once the CRTC is stopped. We thus can't only disable planes right before starting the CRTC as it would start scanning out immediately from old frame buffers until the next vblank. Fix the problem by disabling all planes when stopping the CRTC and wait for the change to take effect. This increases the CRTC stop delay, especially when multiple CRTCs are stopped in one operation as we now wait for one vblank per CRTC. Whether this can be improved needs to be researched. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> --- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index e6a32c4e4040..a40085806f5b 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c @@ -398,6 +398,19 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc) if (!rcrtc->started) return; + /* Disable all planes and wait for the change to take effect. This is + * required as the DSnPR registers are updated on vblank, and no vblank + * will occur once the CRTC is stopped. Disabling planes when starting + * the CRTC thus wouldn't be enough as it would start scanning out + * immediately from old frame buffers until the next vblank. + * + * This increases the CRTC stop delay, especially when multiple CRTCs + * are stopped in one operation as we now wait for one vblank per CRTC. + * Whether this can be improved needs to be researched. + */ + rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR, 0); + drm_crtc_wait_one_vblank(crtc); + /* Disable vertical blanking interrupt reporting. We first need to wait * for page flip completion before stopping the CRTC as userspace * expects page flips to eventually complete. -- Regards, Laurent Pinchart
next prev parent reply other threads:[~2015-05-14 12:34 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-05-14 12:34 [PATCH 1/2] drm: rcar-du: Print the error value when DRM/KMS init fails Laurent Pinchart 2015-05-14 12:34 ` Laurent Pinchart 2015-05-14 12:34 ` Laurent Pinchart [this message] 2015-05-14 12:34 ` [PATCH 2/2] drm: rcar-du: Disable all planes when stopping the CRTC Laurent Pinchart
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1431606842-15522-2-git-send-email-laurent.pinchart+renesas@ideasonboard.com \ --to=laurent.pinchart+renesas@ideasonboard.com \ --cc=dri-devel@lists.freedesktop.org \ --cc=linux-sh@vger.kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.