[PATCH 10/41] drm/bridge: analogix_dp: Don't change psr while bridge is disabled
Sean Paul
seanpaul at chromium.org
Wed Mar 22 08:19:30 PDT 2017
On Wed, Mar 22, 2017 at 09:36:34AM +0100, Andrzej Hajda wrote:
> On 21.03.2017 20:58, Sean Paul wrote:
> > On Thu, Mar 16, 2017 at 02:40:21PM +0100, Andrzej Hajda wrote:
> >> On 10.03.2017 05:32, Sean Paul wrote:
> >>> From: zain wang <wzz at rock-chips.com>
> >>>
> >>> There is a race between AUX CH bring-up and enabling bridge which will
> >>> cause link training to fail. To avoid hitting it, don't change psr state
> >>> while enabling the bridge.
> >>>
> >>> Cc: Tomeu Vizoso <tomeu.vizoso at collabora.com>
> >>> Cc: Sean Paul <seanpaul at chromium.org>
> >>> Signed-off-by: zain wang <wzz at rock-chips.com>
> >>> Signed-off-by: Caesar Wang <wxt at rock-chips.com>
> >>> [seanpaul fixed up the commit message a bit and renamed *_supported to *_enabled]
> >>> Signed-off-by: Sean Paul <seanpaul at chromium.org>
> >> Hmm, beside resetting psr_enable in analogix_dp_bridge_disable I do not
> >> see functional change, or am I blind?
> > The patch also adds a check of psr_enable in analogix_dp_commit. This will avoid
> > trying to enable psr when the bridge is disabled (that's why psr_enable is
> > reset).
>
> Copy/paste from analogix_dp_commit chunk below:
>
> - dp->psr_support = analogix_dp_detect_sink_psr(dp);
> - if (dp->psr_support)
> + dp->psr_enable = analogix_dp_detect_sink_psr(dp);
> + if (dp->psr_enable)
> analogix_dp_enable_sink_psr(dp);
>
>
> What is added here?
I guess this is what I get for skimming, apologies. I'll hopefully do a better
job explaining below.
>
> Regards
> Andrzej
>
> >
> > Sean
> >
> >> Regards
> >> Andrzej
> >>
> >>> ---
> >>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 15 ++++++++-------
> >>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 2 +-
> >>> drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 2 +-
> >>> include/drm/bridge/analogix_dp.h | 2 +-
> >>> 4 files changed, 11 insertions(+), 10 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >>> index 8a8f05fe9da3..64d94a34874d 100644
> >>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >>> @@ -98,20 +98,20 @@ static int analogix_dp_detect_hpd(struct analogix_dp_device *dp)
> >>> return 0;
> >>> }
> >>>
> >>> -int analogix_dp_psr_supported(struct device *dev)
> >>> +int analogix_dp_psr_enabled(struct device *dev)
> >>> {
> >>> struct analogix_dp_device *dp = dev_get_drvdata(dev);
> >>>
> >>> - return dp->psr_support;
> >>> + return dp->psr_enable;
> >>> }
> >>> -EXPORT_SYMBOL_GPL(analogix_dp_psr_supported);
> >>> +EXPORT_SYMBOL_GPL(analogix_dp_psr_enabled);
> >>>
> >>> int analogix_dp_enable_psr(struct device *dev)
> >>> {
> >>> struct analogix_dp_device *dp = dev_get_drvdata(dev);
> >>> struct edp_vsc_psr psr_vsc;
> >>>
> >>> - if (!dp->psr_support)
> >>> + if (!dp->psr_enable)
This gates enabling psr on the panel. Previously it was put in place to avoid
trying to enable psr on devices which did not support it.
> >>> return 0;
> >>>
> >>> /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */
> >>> @@ -134,7 +134,7 @@ int analogix_dp_disable_psr(struct device *dev)
> >>> struct edp_vsc_psr psr_vsc;
> >>> int ret;
> >>>
> >>> - if (!dp->psr_support)
> >>> + if (!dp->psr_enable)
> >>> return 0;
> >>>
> >>> /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */
> >>> @@ -878,8 +878,8 @@ static void analogix_dp_commit(struct analogix_dp_device *dp)
> >>> /* Enable video */
> >>> analogix_dp_start_video(dp);
> >>>
> >>> - dp->psr_support = analogix_dp_detect_sink_psr(dp);
> >>> - if (dp->psr_support)
> >>> + dp->psr_enable = analogix_dp_detect_sink_psr(dp);
> >>> + if (dp->psr_enable)
This probes the hardware to see if psr is supported. If it is, psr_enable will
transition to true. Before this patch, psr_support/psr_enable would be flipped
true on the first modeset and stay that way forever, even when the panel was
turned off.
> >>> analogix_dp_enable_sink_psr(dp);
> >>> }
> >>>
> >>> @@ -1120,6 +1120,7 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
> >>> if (ret)
> >>> DRM_ERROR("failed to setup the panel ret = %d\n", ret);
> >>>
> >>> + dp->psr_enable = false;
By setting psr_enable to false here, the driver ensures that any subsequent calls
to analogix_dp_enable_psr() will return early and will not attempt to change
hardware (that would fail). Once the panel is re-enabled, psr_enable will return
to true if the hardware supports it.
This is why the variable was renamed from psr_support to psr_enable. It no
longer just tracks whether psr is supported, but rather that it is supported and
eligible to be enabled.
Sean
> >>> dp->dpms_mode = DRM_MODE_DPMS_OFF;
> >>> }
> >>>
> >>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> >>> index b039b28d8fcc..e135a42cb19e 100644
> >>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> >>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> >>> @@ -170,7 +170,7 @@ struct analogix_dp_device {
> >>> int dpms_mode;
> >>> int hpd_gpio;
> >>> bool force_hpd;
> >>> - bool psr_support;
> >>> + bool psr_enable;
> >>>
> >>> struct mutex panel_lock;
> >>> bool panel_is_modeset;
> >>> diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> >>> index 64e7e2c0bc58..f44756029478 100644
> >>> --- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> >>> +++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> >>> @@ -83,7 +83,7 @@ static void analogix_dp_psr_set(struct drm_encoder *encoder, bool enabled)
> >>> int vact_end;
> >>> int ret;
> >>>
> >>> - if (!analogix_dp_psr_supported(dp->dev))
> >>> + if (!analogix_dp_psr_enabled(dp->dev))
> >>> return;
> >>>
> >>> dev_dbg(dp->dev, "%s PSR...\n", enabled ? "enable" : "disable");
> >>> diff --git a/include/drm/bridge/analogix_dp.h b/include/drm/bridge/analogix_dp.h
> >>> index c99d6eaef1ac..4fc0165ed3f5 100644
> >>> --- a/include/drm/bridge/analogix_dp.h
> >>> +++ b/include/drm/bridge/analogix_dp.h
> >>> @@ -38,7 +38,7 @@ struct analogix_dp_plat_data {
> >>> struct drm_connector *);
> >>> };
> >>>
> >>> -int analogix_dp_psr_supported(struct device *dev);
> >>> +int analogix_dp_psr_enabled(struct device *dev);
> >>> int analogix_dp_enable_psr(struct device *dev);
> >>> int analogix_dp_disable_psr(struct device *dev);
> >>>
>
--
Sean Paul, Software Engineer, Google / Chromium OS
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