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From: Archit Taneja <architt@codeaurora.org>
To: robdclark@gmail.com
Cc: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
	Archit Taneja <architt@codeaurora.org>
Subject: [PATCH 1/2] drm/msm/dsi: Use correct pm_runtime_put variant during host_init
Date: Fri,  6 Oct 2017 16:27:06 +0530	[thread overview]
Message-ID: <20171006105707.20416-2-architt@codeaurora.org> (raw)
In-Reply-To: <20171006105707.20416-1-architt@codeaurora.org>

The DSI runtime PM suspend/resume callbacks check whether
msm_host->cfg_hnd is non-NULL before trying to enable the bus clocks.
This is done to accommodate early calls to these functions that may
happen before the bus clocks are even initialized.

Calling pm_runtime_put_autosuspend() in dsi_host_init() can result in
racy behaviour since msm_host->cfg_hnd is set very soon after. If the
suspend callback happens too late, we end up trying to disable clocks
that were never enabled, resulting in a bunch of WARN_ON splats.

Use pm_runtime_put_sync() so that the suspend callback is called
immediately.

Reported-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index dbb31a014419..deaf869374ea 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -248,7 +248,7 @@ static const struct msm_dsi_cfg_handler *dsi_get_config(
 	clk_disable_unprepare(ahb_clk);
 disable_gdsc:
 	regulator_disable(gdsc_reg);
-	pm_runtime_put_autosuspend(dev);
+	pm_runtime_put_sync(dev);
 put_clk:
 	clk_put(ahb_clk);
 put_gdsc:
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

  reply	other threads:[~2017-10-06 10:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-06 10:57 [PATCH 0/2] drm/msm: Some runtime PM fixes Archit Taneja
2017-10-06 10:57 ` Archit Taneja [this message]
2017-10-06 14:02   ` [PATCH 1/2] drm/msm/dsi: Use correct pm_runtime_put variant during host_init Daniel Vetter
2017-10-10  3:28     ` Archit Taneja
2017-10-10  8:59       ` Daniel Vetter
2017-10-10 12:07         ` Rob Clark
2017-10-06 10:57 ` [PATCH 2/2] drm/msm/mdp5: Remove extra pm_runtime_put call in mdp5_crtc_cursor_set() Archit Taneja
2017-10-06 11:58 ` [PATCH 0/2] drm/msm: Some runtime PM fixes Nicolas Dechesne

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