From: Doug Anderson <dianders@chromium.org>
To: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
freedreno <freedreno@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>, Rob Clark <robdclark@gmail.com>,
Sean Paul <seanpaul@chromium.org>,
Stephen Boyd <swboyd@chromium.org>,
quic_kalyant <quic_kalyant@quicinc.com>,
"Abhinav Kumar (QUIC)" <quic_abhinavk@quicinc.com>,
"Kuogee Hsieh (QUIC)" <quic_khsieh@quicinc.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
quic_vproddut <quic_vproddut@quicinc.com>,
quic_aravindh@quicinc.com
Subject: Re: [PATCH v6 2/8] drm/msm/dp: wait for hpd high before aux transaction
Date: Thu, 31 Mar 2022 16:22:24 -0700 [thread overview]
Message-ID: <CAD=FV=UtnNTWmMPYPkSJ5qceWspXtZ+hL6UTgSn=rHzd39Y42g@mail.gmail.com> (raw)
In-Reply-To: <1648656179-10347-3-git-send-email-quic_sbillaka@quicinc.com>
Hi,
On Wed, Mar 30, 2022 at 9:03 AM Sankeerth Billakanti
<quic_sbillaka@quicinc.com> wrote:
>
> The source device should ensure the sink is ready before proceeding to
> read the sink capability or performing any aux transactions. The sink
s/performing/perform
> will indicate its readiness by asserting the HPD line. The controller
> driver needs to wait for the hpd line to be asserted by the sink before
> performing any aux transactions.
>
> The eDP sink is assumed to be always connected. It needs power from the
> source and its HPD line will be asserted only after the panel is powered
> on. The panel power will be enabled from the panel-edp driver and only
> after that, the hpd line will be asserted.
>
> Whereas for DP, the sink can be hotplugged and unplugged anytime. The hpd
> line gets asserted to indicate the sink is connected and ready. Hence
> there is no need to wait for the hpd line to be asserted for a DP sink.
>
> Signed-off-by: Sankeerth Billakanti <quic_sbillaka@quicinc.com>
> ---
>
> Changes in v6:
> - Wait for hpd high only for eDP
> - Split into smaller patches
>
> drivers/gpu/drm/msm/dp/dp_aux.c | 13 ++++++++++++-
> drivers/gpu/drm/msm/dp/dp_aux.h | 3 ++-
> drivers/gpu/drm/msm/dp/dp_catalog.c | 13 +++++++++++++
> drivers/gpu/drm/msm/dp/dp_catalog.h | 1 +
> drivers/gpu/drm/msm/dp/dp_display.c | 3 ++-
> 5 files changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
> index 6d36f63..a217c80 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.c
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.c
> @@ -36,6 +36,7 @@ struct dp_aux_private {
> bool initted;
> u32 offset;
> u32 segment;
> + bool is_edp;
>
> struct drm_dp_aux dp_aux;
> };
> @@ -337,6 +338,14 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
> goto exit;
> }
>
> + if (aux->is_edp) {
Adding a comment about _why_ you're doing this just for eDP would
probably be a good idea. Like maybe:
/*
* For eDP it's important to give a reasonably long wait here for HPD
* to be asserted. This is because the panel driver may have _just_
* turned on the panel and then tried to do an AUX transfer. The panel
* driver has no way of knowing when the panel is ready, so it's up
* to us to wait. For DP we never get into this situation so let's
* avoid ever doing the extra long wait for DP.
*/
> @@ -491,7 +500,8 @@ void dp_aux_unregister(struct drm_dp_aux *dp_aux)
> drm_dp_aux_unregister(dp_aux);
> }
>
> -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
> +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
> + bool is_edp)
nit: I think your indentation of the 2nd line isn't quite right.
> diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h b/drivers/gpu/drm/msm/dp/dp_aux.h
> index 82afc8d..c99aeec 100644
> --- a/drivers/gpu/drm/msm/dp/dp_aux.h
> +++ b/drivers/gpu/drm/msm/dp/dp_aux.h
> @@ -16,7 +16,8 @@ void dp_aux_init(struct drm_dp_aux *dp_aux);
> void dp_aux_deinit(struct drm_dp_aux *dp_aux);
> void dp_aux_reconfig(struct drm_dp_aux *dp_aux);
>
> -struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog);
> +struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
> + bool is_edp);
nit: I think your indentation of the 2nd line isn't quite right.
Things are pretty much nits, so FWIW:
Reviewed-by: Douglas Anderson <dianders@chromium.org>
next prev parent reply other threads:[~2022-03-31 23:29 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-30 16:02 [PATCH v6 0/8] Add support for the eDP panel over aux_bus Sankeerth Billakanti
2022-03-30 16:02 ` [PATCH v6 1/8] drm/msm/dp: Add eDP support via aux_bus Sankeerth Billakanti
2022-03-30 23:19 ` Dmitry Baryshkov
2022-03-31 0:33 ` Doug Anderson
2022-03-31 23:22 ` Doug Anderson
2022-04-02 10:37 ` Dmitry Baryshkov
2022-04-02 17:06 ` Doug Anderson
2022-04-02 20:26 ` Dmitry Baryshkov
2022-04-04 20:53 ` Doug Anderson
2022-04-05 12:53 ` Dmitry Baryshkov
2022-04-05 17:02 ` Doug Anderson
2022-04-05 17:36 ` Dmitry Baryshkov
2022-04-05 18:11 ` Doug Anderson
2022-04-07 14:19 ` Sankeerth Billakanti (QUIC)
2022-04-07 17:07 ` Doug Anderson
2022-04-07 20:11 ` Abhinav Kumar
2022-04-07 20:47 ` Doug Anderson
2022-04-07 22:03 ` Abhinav Kumar
2022-04-07 23:34 ` Doug Anderson
2022-04-07 23:46 ` Dmitry Baryshkov
2022-04-08 0:21 ` Doug Anderson
2022-04-08 12:19 ` Dmitry Baryshkov
2022-04-08 13:43 ` Doug Anderson
2022-04-08 14:58 ` Dmitry Baryshkov
2022-04-08 17:23 ` Abhinav Kumar
2022-04-07 23:35 ` Dmitry Baryshkov
2022-04-08 0:20 ` Doug Anderson
2022-04-08 12:13 ` Dmitry Baryshkov
2022-04-08 13:56 ` Doug Anderson
2022-04-08 14:17 ` Dmitry Baryshkov
2022-03-30 16:02 ` [PATCH v6 2/8] drm/msm/dp: wait for hpd high before aux transaction Sankeerth Billakanti
2022-03-31 23:22 ` Doug Anderson [this message]
2022-04-04 12:43 ` Sankeerth Billakanti (QUIC)
2022-03-30 16:02 ` [PATCH v6 3/8] drm/msm/dp: Support only IRQ_HPD and REPLUG interrupts for eDP Sankeerth Billakanti
2022-03-31 23:22 ` Doug Anderson
2022-04-04 12:56 ` Sankeerth Billakanti (QUIC)
2022-03-30 16:02 ` [PATCH v6 4/8] drm/msm/dp: avoid handling masked interrupts Sankeerth Billakanti
2022-03-30 22:16 ` Dmitry Baryshkov
2022-03-31 5:53 ` Sankeerth Billakanti (QUIC)
2022-03-31 10:10 ` Dmitry Baryshkov
2022-03-31 11:04 ` Sankeerth Billakanti
2022-03-31 11:06 ` Dmitry Baryshkov
2022-04-04 17:56 ` Sankeerth Billakanti (QUIC)
2022-03-30 16:02 ` [PATCH v6 5/8] drm/msm/dp: prevent multiple votes for dp resources Sankeerth Billakanti
2022-03-31 23:23 ` Doug Anderson
2022-04-08 16:14 ` Dmitry Baryshkov
2022-04-08 17:12 ` Sankeerth Billakanti
2022-04-08 18:02 ` Dmitry Baryshkov
2022-03-30 16:02 ` [PATCH v6 6/8] drm/msm/dp: remove unnecessary delay during boot Sankeerth Billakanti
2022-03-31 23:23 ` Doug Anderson
2022-04-04 13:52 ` Sankeerth Billakanti (QUIC)
2022-04-04 21:13 ` Dmitry Baryshkov
2022-04-07 12:40 ` Sankeerth Billakanti (QUIC)
2022-03-30 16:02 ` [PATCH v6 7/8] drm/msm/dp: Support edp/dp without hpd Sankeerth Billakanti
2022-03-31 23:23 ` Doug Anderson
2022-04-04 18:32 ` Sankeerth Billakanti (QUIC)
2022-04-04 21:15 ` Dmitry Baryshkov
2022-04-07 12:41 ` Sankeerth Billakanti (QUIC)
2022-03-30 16:02 ` [PATCH v6 8/8] drm/msm/dp: Handle eDP mode_valid differently from dp Sankeerth Billakanti
2022-03-30 22:08 ` Dmitry Baryshkov
2022-03-31 6:02 ` Sankeerth Billakanti (QUIC)
2022-03-31 23:24 ` Doug Anderson
2022-04-04 18:20 ` Sankeerth Billakanti (QUIC)
2022-04-04 21:29 ` Dmitry Baryshkov
2022-04-07 14:05 ` Sankeerth Billakanti (QUIC)
2022-04-08 12:08 ` Dmitry Baryshkov
2022-04-08 15:50 ` Sankeerth Billakanti
2022-04-08 16:47 ` Dmitry Baryshkov
2022-04-08 17:38 ` Sankeerth Billakanti
2022-04-08 18:06 ` Dmitry Baryshkov
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