From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Douglas Anderson <dianders@chromium.org>,
Rob Clark <robdclark@gmail.com>,
Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
Sean Paul <sean@poorly.run>, Stephen Boyd <swboyd@chromium.org>,
Vinod Koul <vkoul@kernel.org>,
dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] drm/msm/dsi: only powerup at modeset time if "early_poweron" modparam
Date: Thu, 12 May 2022 23:58:59 +0300 [thread overview]
Message-ID: <e8d75148-22ee-5809-fc65-d0fb38ad4876@linaro.org> (raw)
In-Reply-To: <20220512135134.v3.1.Ia196e35ad985059e77b038a41662faae9e26f411@changeid>
On 12/05/2022 23:52, Douglas Anderson wrote:
> Commit 7d8e9a90509f ("drm/msm/dsi: move DSI host powerup to modeset
> time") caused sc7180 Chromebooks that use the parade-ps8640 bridge
> chip to fail to turn the display back on after it turns off.
>
> Unfortunately, it doesn't look easy to fix the parade-ps8640 driver to
> handle the new power sequence. The Linux driver has almost nothing in
> it and most of the logic for this bridge chip is in black-box firmware
> that the bridge chip uses.
>
> Also unfortunately, reverting the patch will break "tc358762".
>
> The long term solution here is probably Dave Stevenson's series [1]
> that would give more flexibility. However, that is likely not a quick
> fix.
>
> For the short term, let's introduce a module parameter that selects
> between the two behaviors. This is a short term hack but at least can
> keep both users working. We'll default the value of the module
> parameter to the old behavior. Given that the old behavior has existed
> for longer it's probably a safer default.
>
> [1] https://lore.kernel.org/r/cover.1646406653.git.dave.stevenson@raspberrypi.com
>
> Fixes: 7d8e9a90509f ("drm/msm/dsi: move DSI host powerup to modeset time")
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Two minor issues below.
> ---
>
> Changes in v3:
> - No longer a revert; now a module parameter.
>
> Changes in v2:
> - Remove the mud from my face.
>
> drivers/gpu/drm/msm/dsi/dsi_manager.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> index 50b987658b1f..2bf4123ef5df 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
> @@ -34,6 +34,10 @@ static struct msm_dsi_manager msm_dsim_glb;
> #define IS_SYNC_NEEDED() (msm_dsim_glb.is_sync_needed)
> #define IS_MASTER_DSI_LINK(id) (msm_dsim_glb.master_dsi_link_id == id)
>
> +bool early_poweron;
> +MODULE_PARM_DESC(early_poweron, "Power DSI controller early");
> +module_param(early_poweron, bool, 0600);
Nit: dsi_early_poweron (to be clear that it related to DSI only).
I thought about suggesting 'dsi_no_early_poweron' instead to catch
possible issues with other bridges. But... I think with Dave's series
will have to enable bridges one by one, so it doesn't make real sense.
> +
> static inline struct msm_dsi *dsi_mgr_get_dsi(int id)
> {
> return msm_dsim_glb.dsi[id];
> @@ -389,6 +393,9 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
> if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
> return;
>
> + if (!early_poweron)
> + dsi_mgr_bridge_power_on(bridge);
> +
> /* Always call panel functions once, because even for dual panels,
> * there is only one drm_panel instance.
> */
> @@ -570,7 +577,8 @@ static void dsi_mgr_bridge_mode_set(struct drm_bridge *bridge,
> if (is_bonded_dsi && other_dsi)
> msm_dsi_host_set_display_mode(other_dsi->host, adjusted_mode);
>
> - dsi_mgr_bridge_power_on(bridge);
> + if (early_poweron)
> + dsi_mgr_bridge_power_on(bridge);
> }
>
> static enum drm_mode_status dsi_mgr_bridge_mode_valid(struct drm_bridge *bridge,
--
With best wishes
Dmitry
next prev parent reply other threads:[~2022-05-12 20:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-12 20:52 [PATCH v3] drm/msm/dsi: only powerup at modeset time if "early_poweron" modparam Douglas Anderson
2022-05-12 20:58 ` Dmitry Baryshkov [this message]
2022-05-12 22:01 ` Doug Anderson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e8d75148-22ee-5809-fc65-d0fb38ad4876@linaro.org \
--to=dmitry.baryshkov@linaro.org \
--cc=airlied@linux.ie \
--cc=bjorn.andersson@linaro.org \
--cc=daniel@ffwll.ch \
--cc=dave.stevenson@raspberrypi.com \
--cc=dianders@chromium.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=freedreno@lists.freedesktop.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=quic_abhinavk@quicinc.com \
--cc=robdclark@gmail.com \
--cc=sean@poorly.run \
--cc=swboyd@chromium.org \
--cc=vkoul@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).