On Fri, 2017-05-12 at 11:10 -0700, Puthikorn Voravootivat wrote:
>
>
> On Fri, May 12, 2017 at 6:14 AM, Jani Nikula
> <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Fri, 12 May 2017, "Pandiyan, Dhinakaran"
> <dhinakaran.pandiyan@xxxxxxxxx> wrote:
> > On Thu, 2017-05-11 at 16:02 -0700, Puthikorn Voravootivat
> wrote:
> >> There are some panel that
> >> (1) does not support display backlight enable via AUX
> >> (2) support display backlight adjustment via AUX
> >> (3) support display backlight enable via eDP BL_ENABLE pin
> >>
> >> The current driver required that (1) must be support to
> enable (2).
> >> This patch drops that requirement.
> >>
> >
> > You sent this version before I finished my follow-up
> questions, copying
> > the conversation here for context.
>
> Puthikorn, please don't send new versions before the review is
> addressed.
> Sorry I thought I was explained it clear enough.
>
> Pushed patches 1, 2, 5, and 7. Thanks for the patches and
> review.
>
> BR,
> Jani.
>
> > DK: Won't DP_EDP_BACKLIGHT_AUX_ENABLE_CAP be 1 always? The
> code below,
> > in
> > intel_dp_aux_display_control_capable(), makes sure
> > DP_EDP_BACKLIGHT_PIN_ENABLE_CAP=0. The spec says at least
> one of these
> > has to be 1.
> >
> > Puthikorn: We will drop the
> DP_EDP_BACKLIGHT_PIN_ENABLE_CAP != 0 check
> > in next patch set.
> > This patch adds check here to prepare for that.
> >
> >
> > 1) So, this patch does not really fix what the commit
> message claims
> > because it is dependent on the following patch. Does it make
> sense to
> > remove this check in this patch? That way, this patch by
> itself is the
> > fix that the commit message says.
> >
> > - !((intel_dp->edp_dpcd[1] &
> DP_EDP_BACKLIGHT_PIN_ENABLE_CAP)
> >
>
> Sure. I can remove this here and adds it in next patch instead.
>
>
> >
> > 2) If a panel supports backlight enable via AUX and
> BL_ENABLE pin, this
> > patch (along with the next) enables backlight twice, doesn't
> it?
> > _intel_edp_backlight_on(intel_dp) in intel_dp.c is called
> > unconditionally after intel_dp_aux_enable_backlight(). I
> don't know how
> > likely this configuration is or if it's alright to enable
> via both AUX
> > and BL_ENABLE pin.
> >
>
> The eDP spec did not mention this case explicitly.
> But it should not hurt to enable backlight twice as we want the
> backlight to be enabled anyway.
>
Hope so, at least a TODO would be a reasonable warning.
> >
> >
> >
> >> Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx>
> >> ---
> >> drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 5 ++++-
> >> 1 file changed, 4 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> >> index 870c03fc0f3a..c22712762957 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
> >> @@ -28,6 +28,10 @@ static void
> set_aux_backlight_enable(struct intel_dp *intel_dp, bool
> enable)
> >> {
> >> uint8_t reg_val = 0;
> >>
> >> + /* Early return when display use other mechanism to
> enable backlight. */
> >> + if (!(intel_dp->edp_dpcd[1] &
> DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
> >> + return;
> >> +
> >> if (drm_dp_dpcd_readb(&intel_dp->aux,
> DP_EDP_DISPLAY_CONTROL_REGISTER,
> >> ®_val) < 0) {
> >> DRM_DEBUG_KMS("Failed to read DPCD register 0x
> %x\n",
> >> @@ -164,7 +168,6 @@
> intel_dp_aux_display_control_capable(struct intel_connector
> *connector)
> >> * the panel can support backlight control over the
> aux channel
> >> */
> >> if (intel_dp->edp_dpcd[1] &
> DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
> >> - (intel_dp->edp_dpcd[1] &
> DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
> >> (intel_dp->edp_dpcd[2] &
> DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
> >> !((intel_dp->edp_dpcd[1] &
> DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
> >> (intel_dp->edp_dpcd[2] &
> DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
> >
>
>
> --
> Jani Nikula, Intel Open Source Technology Center
>
>
>
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