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    SubjectRe: [PATCH v1 2/2] drm/bridge: analogix_dp: turn off the panel when eDP need to disable
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    Sean,

    Oops, sorry about miss your suggest :(

    On 07/22/2016 11:03 PM, Sean Paul wrote:
    > On Thu, Jul 21, 2016 at 9:00 PM, Yakir Yang <ykk@rock-chips.com> wrote:
    >> Sean,
    >>
    >> Thanks for your fast respond :-)
    >>
    >> But this patch is not the latest one, I have upgraded this to "v1.1" version
    >> to fix the eDP can't be disabled problem:
    >> [PATCH v1.1 2/2] drm/bridge: analogix_dp: turn off the panel when eDP
    >> need to disable
    >> Changes in v1.1: - unprepare the panel at the end of
    >> bridge->disable() function
    >>
    >> In spite of this, I would take your comments with my "v1.1" patch.
    >>
    >> On 07/21/2016 10:28 PM, Sean Paul wrote:
    >>
    >> On Thu, Jul 21, 2016 at 9:14 AM, Yakir Yang <ykk@rock-chips.com> wrote:
    >>
    >> Some panels (like Sharp LQ123P1JX31) need to be turn off when eDP
    >> controller stop to send valid video signal, otherwhise panel would
    >> go burn in, and keep flicker and flicker.
    >>
    >> So it's better to turn off the panel when eDP need to disable, and
    >> we need to turn on the panel in connector->detect() callback, so
    >> that driver would detect panel status rightly.
    >>
    >> Signed-off-by: Yakir Yang <ykk@rock-chips.com>
    >> ---
    >> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 18 ++++++++++--------
    >> 1 file changed, 10 insertions(+), 8 deletions(-)
    >>
    >> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
    >> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
    >> index 32715da..ea059b3 100644
    >> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
    >> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
    >> @@ -961,6 +961,14 @@ analogix_dp_detect(struct drm_connector *connector,
    >> bool force)
    >> {
    >> struct analogix_dp_device *dp = to_dp(connector);
    >>
    >> + /*
    >> + * Panle would prepare for several times here, but don't worry it
    >>
    >> s/Panle/Panel/
    >>
    >>
    >> Done
    >>
    >> + * would only enable the hardware at the first prepare time.
    >>
    >> Errr, this shouldn't go in detect. How about putting this in
    >> bridge_enable instead?
    >>
    >>
    >> Nope, if we put this in bridge_enable, then eDP would never be enabled.
    >> Here're the calling flow.
    >>
    >> --> analogix_dp_probe
    >> --> analogix_dp_bind # we still haven't prepared the panel here, that
    >> means panel have been powered up
    >> --> analogix_dp_detect # Oops, losing panel valid hotplug signal, cause
    >> panel have been powered up
    >> --> ** Keep detecting **
    >
    > Yeah, after playing around with the patch yesterday I discovered this
    > for myself. I still don't think detect() should be changing hardware
    > state. Perhaps you could add a matching unprepare() after you attempt
    > to detect the panel?

    Hmm, I don't understand the meaning of "add a matching unprepare()".

    I didn't see there is an unprepare() callback in drm_crtc_helper.h, would
    you like to share some simple code :-D

    Thanks,
    - Yakir

    > Sean
    >
    >> + */
    >> + if (dp->plat_data->panel)
    >> + if (drm_panel_prepare(dp->plat_data->panel))
    >>
    >> Personally, I don't like doing work in a conditional since you're
    >> throwing the return code away. Could you break this out into:
    >>
    >> ret = drm_panel_prepare(dp->plat_data->panel);
    >> if (ret)
    >> DRM_ERROR("failed to setup the panel ret=%d\n", ret);
    >>
    >>
    >> Okay
    >>
    >>
    >> + DRM_ERROR("failed to setup the panel\n");
    >> +
    >> if (analogix_dp_detect_hpd(dp))
    >> return connector_status_disconnected;
    >>
    >> @@ -1063,7 +1071,8 @@ static void analogix_dp_bridge_disable(struct
    >> drm_bridge *bridge)
    >> return;
    >>
    >> if (dp->plat_data->panel) {
    >> - if (drm_panel_disable(dp->plat_data->panel)) {
    >> + if (drm_panel_disable(dp->plat_data->panel) ||
    >> + drm_panel_unprepare(dp->plat_data->panel)) {
    >>
    >> Same comment here, please break this out into separate statements for
    >> better readability/logging.
    >>
    >>
    >> Okay,
    >>
    >>
    >> Thanks,
    >> - Yakir
    >>
    >>
    >> DRM_ERROR("failed to disable the panel\n");
    >> return;
    >> }
    >> @@ -1333,13 +1342,6 @@ int analogix_dp_bind(struct device *dev, struct
    >> drm_device *drm_dev,
    >>
    >> phy_power_on(dp->phy);
    >>
    >> - if (dp->plat_data->panel) {
    >> - if (drm_panel_prepare(dp->plat_data->panel)) {
    >> - DRM_ERROR("failed to setup the panel\n");
    >> - return -EBUSY;
    >> - }
    >> - }
    >> -
    >> analogix_dp_init_dp(dp);
    >>
    >> ret = devm_request_threaded_irq(&pdev->dev, dp->irq,
    >> --
    >> 1.9.1
    >>
    >>
    >>
    >>
    >>
    >
    >


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