| From 419e91ea3143bf26991442465ac64d9461e98d96 Mon Sep 17 00:00:00 2001 |
| From: Wayne Lin <Wayne.Lin@amd.com> |
| Date: Wed, 24 Feb 2021 18:15:20 +0800 |
| Subject: drm/dp_mst: Revise broadcast msg lct & lcr |
| |
| From: Wayne Lin <Wayne.Lin@amd.com> |
| |
| commit 419e91ea3143bf26991442465ac64d9461e98d96 upstream. |
| |
| [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 |
| Reviewed-by: Lyude Paul <lyude@redhat.com> |
| Signed-off-by: Lyude Paul <lyude@redhat.com> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20210224101521.6713-2-Wayne.Lin@amd.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/gpu/drm/drm_dp_mst_topology.c | 13 +++++++++---- |
| 1 file changed, 9 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/gpu/drm/drm_dp_mst_topology.c |
| +++ b/drivers/gpu/drm/drm_dp_mst_topology.c |
| @@ -2829,10 +2829,15 @@ static int set_hdr_from_dst_qlock(struct |
| 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; |
| } |