While testing MST hotplug events on daisy chain monitors, find out that CLEAR_PAYLOAD_ID_TABLE is not broadcasted and payload id table is not reset. Dig in deeper and find out two parts needed to be fixed.
1. Link_Count_Total & Link_Count_Remaining of Broadcast message are incorrect. Should set lct=1 & lcr=6 2. CLEAR_PAYLOAD_ID_TABLE request message is not set as path broadcast request message. Should fix this.
Changes since v1: *Refer to the suggestion from Ville Syrjala. While preparing hdr-rad, take broadcast case into consideration.
Wayne Lin (2): drm/dp_mst: Revise broadcast msg lct & lcr drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast
drivers/gpu/drm/drm_dp_mst_topology.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
-- 2.17.1
[Why & How] According to DP spec, broadcast message LCT equals to 1 and LCR equals to 6. Current implementation is incorrect. Fix it. In addition, revise a bit the hdr->rad handling to include broadcast case.
Signed-off-by: Wayne Lin Wayne.Lin@amd.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_dp_mst_topology.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 17dbed0a9800..f11b3f718031 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2727,10 +2727,15 @@ static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr, else hdr->broadcast = 0; hdr->path_msg = txmsg->path_msg; - hdr->lct = mstb->lct; - hdr->lcr = mstb->lct - 1; - if (mstb->lct > 1) - memcpy(hdr->rad, mstb->rad, mstb->lct / 2); + if (hdr->broadcast) { + hdr->lct = 1; + hdr->lcr = 6; + } else { + hdr->lct = mstb->lct; + hdr->lcr = mstb->lct - 1; + } + + memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
return 0; }
[Why & How] According to DP spec, CLEAR_PAYLOAD_ID_TABLE is a path broadcast request message and current implementation is incorrect. Fix it.
Signed-off-by: Wayne Lin Wayne.Lin@amd.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index f11b3f718031..c32b98389349 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -1072,6 +1072,7 @@ static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE; drm_dp_encode_sideband_req(&req, msg); + msg->path_msg = true; }
static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, @@ -2722,7 +2723,8 @@ static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
req_type = txmsg->msg[0] & 0x7f; if (req_type == DP_CONNECTION_STATUS_NOTIFY || - req_type == DP_RESOURCE_STATUS_NOTIFY) + req_type == DP_RESOURCE_STATUS_NOTIFY || + req_type == DP_CLEAR_PAYLOAD_ID_TABLE) hdr->broadcast = 1; else hdr->broadcast = 0;
also - I meant to reply to v2, not v1 :). Just so you don't worry that I pushed the wrong patch series version
On Wed, 2021-02-24 at 18:15 +0800, Wayne Lin wrote:
While testing MST hotplug events on daisy chain monitors, find out that CLEAR_PAYLOAD_ID_TABLE is not broadcasted and payload id table is not reset. Dig in deeper and find out two parts needed to be fixed.
- Link_Count_Total & Link_Count_Remaining of Broadcast message are
incorrect. Should set lct=1 & lcr=6 2. CLEAR_PAYLOAD_ID_TABLE request message is not set as path broadcast request message. Should fix this.
Changes since v1: *Refer to the suggestion from Ville Syrjala. While preparing hdr-rad, take broadcast case into consideration.
Wayne Lin (2): drm/dp_mst: Revise broadcast msg lct & lcr drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast
drivers/gpu/drm/drm_dp_mst_topology.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
-- 2.17.1
[AMD Public Use]
Thanks Lyude!
Regards, Wayne
-----Original Message----- From: Lyude Paul lyude@redhat.com Sent: Thursday, February 25, 2021 2:09 AM To: Lin, Wayne Wayne.Lin@amd.com; dri-devel@lists.freedesktop.org Cc: ville.syrjala@linux.intel.com; stable@vger.kernel.org; Kazlauskas, Nicholas Nicholas.Kazlauskas@amd.com; Wentland, Harry Harry.Wentland@amd.com; Zuo, Jerry Jerry.Zuo@amd.com; Brol, Eryk Eryk.Brol@amd.com; Zhuo, Qingqing Qingqing.Zhuo@amd.com Subject: Re: [PATCH v2 0/2] Set CLEAR_PAYLOAD_ID_TABLE as broadcast request
also - I meant to reply to v2, not v1 :). Just so you don't worry that I pushed the wrong patch series version
On Wed, 2021-02-24 at 18:15 +0800, Wayne Lin wrote:
While testing MST hotplug events on daisy chain monitors, find out that CLEAR_PAYLOAD_ID_TABLE is not broadcasted and payload id table is not reset. Dig in deeper and find out two parts needed to be fixed.
- Link_Count_Total & Link_Count_Remaining of Broadcast message are
incorrect. Should set lct=1 & lcr=6 2. CLEAR_PAYLOAD_ID_TABLE request message is not set as path broadcast request message. Should fix this.
Changes since v1: *Refer to the suggestion from Ville Syrjala. While preparing hdr-rad, take broadcast case into consideration.
Wayne Lin (2): drm/dp_mst: Revise broadcast msg lct & lcr drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast
drivers/gpu/drm/drm_dp_mst_topology.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
-- 2.17.1
-- Sincerely, Lyude Paul (she/her) Software Engineer at Red Hat
Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've asked me a question, are waiting for a review/merge on a patch, etc. and I haven't responded in a while, please feel free to send me another email to check on my status. I don't bite!
linux-stable-mirror@lists.linaro.org
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Lin, Wayne -
Lyude Paul -
Wayne Lin