All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stephen Boyd <swboyd@chromium.org>
To: Rob Clark <robdclark@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	Sean Paul <sean@poorly.run>,
	dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
	Kuogee Hsieh <khsieh@codeaurora.org>
Subject: [PATCH] drm/msm/dp: Restore aux retry tuning logic
Date: Fri, 26 Feb 2021 13:08:21 -0800	[thread overview]
Message-ID: <20210226210821.682107-1-swboyd@chromium.org> (raw)

In commit 9fc418430c65 ("drm/msm/dp: unplug interrupt missed after
irq_hpd handler") we dropped a reset of the aux phy during aux transfers
because resetting the phy during active communication caused us to miss
an hpd irq in some cases. Unfortunately, we also dropped the part of the
code that changes the aux phy tuning when an aux transfer fails due to a
timeout. That part of the code was calling into the phy driver to
reconfigure the aux TX swing controls, working around poor channel
quality. Let's restore this phy setting code so that aux channel
communication is more reliable.

Cc: Kuogee Hsieh <khsieh@codeaurora.org>
Fixes: 9fc418430c65 ("drm/msm/dp: unplug interrupt missed after irq_hpd handler")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---

Noticed by code inspection and based on bug reports where the aux channel
stops working once the commit this is fixing is applied.

 drivers/gpu/drm/msm/dp/dp_aux.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 1c6e1d2b947c..7c22bfe0fc7d 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -32,6 +32,8 @@ struct dp_aux_private {
 	struct drm_dp_aux dp_aux;
 };
 
+#define MAX_AUX_RETRIES			5
+
 static const char *dp_aux_get_error(u32 aux_error)
 {
 	switch (aux_error) {
@@ -377,6 +379,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 	ret = dp_aux_cmd_fifo_tx(aux, msg);
 
 	if (ret < 0) {
+		if (aux->native) {
+			aux->retry_cnt++;
+			if (!(aux->retry_cnt % MAX_AUX_RETRIES))
+				dp_catalog_aux_update_cfg(aux->catalog);
+		}
 		usleep_range(400, 500); /* at least 400us to next try */
 		goto unlock_exit;
 	}

base-commit: 8b83369ddcb3fb9cab5c1088987ce477565bb630
-- 
https://chromeos.dev


WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <swboyd@chromium.org>
To: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	Kuogee Hsieh <khsieh@codeaurora.org>,
	freedreno@lists.freedesktop.org
Subject: [PATCH] drm/msm/dp: Restore aux retry tuning logic
Date: Fri, 26 Feb 2021 13:08:21 -0800	[thread overview]
Message-ID: <20210226210821.682107-1-swboyd@chromium.org> (raw)

In commit 9fc418430c65 ("drm/msm/dp: unplug interrupt missed after
irq_hpd handler") we dropped a reset of the aux phy during aux transfers
because resetting the phy during active communication caused us to miss
an hpd irq in some cases. Unfortunately, we also dropped the part of the
code that changes the aux phy tuning when an aux transfer fails due to a
timeout. That part of the code was calling into the phy driver to
reconfigure the aux TX swing controls, working around poor channel
quality. Let's restore this phy setting code so that aux channel
communication is more reliable.

Cc: Kuogee Hsieh <khsieh@codeaurora.org>
Fixes: 9fc418430c65 ("drm/msm/dp: unplug interrupt missed after irq_hpd handler")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---

Noticed by code inspection and based on bug reports where the aux channel
stops working once the commit this is fixing is applied.

 drivers/gpu/drm/msm/dp/dp_aux.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index 1c6e1d2b947c..7c22bfe0fc7d 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -32,6 +32,8 @@ struct dp_aux_private {
 	struct drm_dp_aux dp_aux;
 };
 
+#define MAX_AUX_RETRIES			5
+
 static const char *dp_aux_get_error(u32 aux_error)
 {
 	switch (aux_error) {
@@ -377,6 +379,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 	ret = dp_aux_cmd_fifo_tx(aux, msg);
 
 	if (ret < 0) {
+		if (aux->native) {
+			aux->retry_cnt++;
+			if (!(aux->retry_cnt % MAX_AUX_RETRIES))
+				dp_catalog_aux_update_cfg(aux->catalog);
+		}
 		usleep_range(400, 500); /* at least 400us to next try */
 		goto unlock_exit;
 	}

base-commit: 8b83369ddcb3fb9cab5c1088987ce477565bb630
-- 
https://chromeos.dev

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

             reply	other threads:[~2021-02-26 21:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-26 21:08 Stephen Boyd [this message]
2021-02-26 21:08 ` [PATCH] drm/msm/dp: Restore aux retry tuning logic Stephen Boyd
2021-05-26 19:03 ` patchwork-bot+linux-arm-msm

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=20210226210821.682107-1-swboyd@chromium.org \
    --to=swboyd@chromium.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=freedreno@lists.freedesktop.org \
    --cc=khsieh@codeaurora.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=robdclark@gmail.com \
    --cc=sean@poorly.run \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.