linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Eric Anholt <eric@anholt.net>
To: dri-devel@lists.freedesktop.org,
	Thierry Reding <thierry.reding@gmail.com>
Cc: linux-kernel@vger.kernel.org, Eric Anholt <eric@anholt.net>
Subject: [PATCH 1/2] drm/vc4: Skip ULPS latching when we're in that ULPS state already.
Date: Tue, 31 Oct 2017 12:32:57 -0700	[thread overview]
Message-ID: <20171031193258.17373-1-eric@anholt.net> (raw)

It seems that trying to go from unlatched to unlatched will time out
waiting for STOP, and we can just skip that.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
index 94085f8bcd68..8aa897835118 100644
--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -753,6 +753,11 @@ static void vc4_dsi_ulps(struct vc4_dsi *dsi, bool ulps)
 			 (dsi->lanes > 2 ? DSI1_STAT_PHY_D2_STOP : 0) |
 			 (dsi->lanes > 3 ? DSI1_STAT_PHY_D3_STOP : 0));
 	int ret;
+	bool ulps_currently_enabled = (DSI_PORT_READ(PHY_AFEC0) &
+				       DSI_PORT_BIT(PHY_AFEC0_LATCH_ULPS));
+
+	if (ulps == ulps_currently_enabled)
+		return;
 
 	DSI_PORT_WRITE(STAT, stat_ulps);
 	DSI_PORT_WRITE(PHYC, DSI_PORT_READ(PHYC) | phyc_ulps);
-- 
2.15.0

             reply	other threads:[~2017-10-31 19:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-31 19:32 Eric Anholt [this message]
2017-10-31 19:32 ` [PATCH 2/2] drm/panel: Enable DSI transactions on the RPi panel Eric Anholt
2018-04-30  9:04   ` Boris Brezillon
2018-04-30  9:27   ` Thierry Reding
2018-04-30 21:04     ` Eric Anholt
2018-04-30  9:03 ` [PATCH 1/2] drm/vc4: Skip ULPS latching when we're in that ULPS state already Boris Brezillon

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=20171031193258.17373-1-eric@anholt.net \
    --to=eric@anholt.net \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=thierry.reding@gmail.com \
    /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: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).