From d89f6048bdcb6a56abb396c584747d5eeae650db Mon Sep 17 00:00:00 2001 From: Harry Wentland Date: Thu, 22 Apr 2021 19:10:52 -0400 Subject: [PATCH] drm/amd/display: Reject non-zero src_y and src_x for video planes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [Why] This hasn't been well tested and leads to complete system hangs on DCN1 based systems, possibly others. The system hang can be reproduced by gesturing the video on the YouTube Android app on ChromeOS into full screen. [How] Reject atomic commits with non-zero drm_plane_state.src_x or src_y values. v2: - Add code comment describing the reason we're rejecting non-zero src_x and src_y - Drop gerrit Change-Id - Add stable CC - Based on amd-staging-drm-next v3: removed trailing whitespace Signed-off-by: Harry Wentland Cc: stable@vger.kernel.org Cc: nicholas.kazlauskas@amd.com Cc: amd-gfx@lists.freedesktop.org Cc: alexander.deucher@amd.com Cc: Roman.Li@amd.com Cc: hersenxs.wu@amd.com Cc: danny.wang@amd.com Reviewed-by: Nicholas Kazlauskas Acked-by: Christian König Reviewed-by: Hersen Wu Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index a0c8c41..deec7e0 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4008,6 +4008,23 @@ static int fill_dc_scaling_info(const struct drm_plane_state *state, scaling_info->src_rect.x = state->src_x >> 16; scaling_info->src_rect.y = state->src_y >> 16; + /* + * For reasons we don't (yet) fully understand a non-zero + * src_y coordinate into an NV12 buffer can cause a + * system hang. To avoid hangs (and maybe be overly cautious) + * let's reject both non-zero src_x and src_y. + * + * We currently know of only one use-case to reproduce a + * scenario with non-zero src_x and src_y for NV12, which + * is to gesture the YouTube Android app into full screen + * on ChromeOS. + */ + if (state->fb && + state->fb->format->format == DRM_FORMAT_NV12 && + (scaling_info->src_rect.x != 0 || + scaling_info->src_rect.y != 0)) + return -EINVAL; + scaling_info->src_rect.width = state->src_w >> 16; if (scaling_info->src_rect.width == 0) return -EINVAL; -- 2.7.4