I've already picked this up. Can you send a follow up patch with just the coverity fix?
Alex
On Fri, Nov 18, 2022 at 2:17 PM Lyude Paul lyude@redhat.com wrote:
JFYI, Coverity pointed out one more issue with this series so I'm going to send out a respin real quick to fix it. It's just a missing variable assignment (we leave ret unassigned by mistake in pre_compute_mst_dsc_configs()) so I will carry over your r-b on it.
On Wed, 2022-11-16 at 04:39 +0000, Lin, Wayne wrote:
[Public]
All the patch set looks good to me. Feel free to add: Reviewed-by: Wayne Lin Wayne.Lin@amd.com
Again, thank you Lyude for helping on this!!!
Regards, Wayne
-----Original Message----- From: Lyude Paul lyude@redhat.com Sent: Tuesday, November 15, 2022 6:18 AM To: amd-gfx@lists.freedesktop.org Cc: Wentland, Harry Harry.Wentland@amd.com; stable@vger.kernel.org; Li, Sun peng (Leo) Sunpeng.Li@amd.com; Siqueira, Rodrigo Rodrigo.Siqueira@amd.com; Deucher, Alexander Alexander.Deucher@amd.com; Koenig, Christian Christian.Koenig@amd.com; Pan, Xinhui Xinhui.Pan@amd.com; David Airlie airlied@gmail.com; Daniel Vetter daniel@ffwll.ch; Kazlauskas, Nicholas Nicholas.Kazlauskas@amd.com; Pillai, Aurabindo Aurabindo.Pillai@amd.com; Li, Roman Roman.Li@amd.com; Zuo, Jerry Jerry.Zuo@amd.com; Wu, Hersen hersenxs.wu@amd.com; Lin, Wayne Wayne.Lin@amd.com; Thomas Zimmermann tzimmermann@suse.de; Mahfooz, Hamza Hamza.Mahfooz@amd.com; Hung, Alex Alex.Hung@amd.com; Mikita Lipski mikita.lipski@amd.com; Liu, Wenjing Wenjing.Liu@amd.com; Francis, David David.Francis@amd.com; open list:DRM DRIVERS <dri- devel@lists.freedesktop.org>; open list linux-kernel@vger.kernel.org Subject: [PATCH v2 1/4] drm/amdgpu/mst: Stop ignoring error codes and deadlocking
It appears that amdgpu makes the mistake of completely ignoring the return values from the DP MST helpers, and instead just returns a simple true/false. In this case, it seems to have come back to bite us because as a result of simply returning false from compute_mst_dsc_configs_for_state(), amdgpu had no way of telling when a deadlock happened from these helpers. This could definitely result in some kernel splats.
V2:
- Address Wayne's comments (fix another bunch of spots where we weren't passing down return codes)
Signed-off-by: Lyude Paul lyude@redhat.com Fixes: 8c20a1ed9b4f ("drm/amd/display: MST DSC compute fair share") Cc: Harry Wentland harry.wentland@amd.com Cc: stable@vger.kernel.org # v5.6+
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 18 +- .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 235 ++++++++++------ -- .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 12 +- 3 files changed, 147 insertions(+), 118 deletions(-)
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 0db2a88cd4d7b..852a2100c6b38 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6462,7 +6462,7 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, struct drm_connector_state *new_con_state; struct amdgpu_dm_connector *aconnector; struct dm_connector_state *dm_conn_state;
- int i, j;
int i, j, ret; int vcpi, pbn_div, pbn, slot_num = 0;
for_each_new_connector_in_state(state, connector,
new_con_state, i) { @@ -6509,8 +6509,11 @@ static int dm_update_mst_vcpi_slots_for_dsc(struct drm_atomic_state *state, dm_conn_state->pbn = pbn; dm_conn_state->vcpi_slots = slot_num;
drm_dp_mst_atomic_enable_dsc(state, aconnector-port, dm_conn_state->pbn,
false);
ret = drm_dp_mst_atomic_enable_dsc(state,aconnector->port,
dm_conn_state-pbn, false);
if (ret < 0)return ret;continue; }@@ -9523,10 +9526,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
#if defined(CONFIG_DRM_AMD_DC_DCN) if (dc_resource_is_dsc_encoding_supported(dc)) {
if (!pre_validate_dsc(state, &dm_state, vars)) {ret = -EINVAL;
ret = pre_validate_dsc(state, &dm_state, vars);if (ret != 0) goto fail;
}#endif
@@ -9621,9 +9623,9 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev, }
#if defined(CONFIG_DRM_AMD_DC_DCN)
if (!compute_mst_dsc_configs_for_state(state, dm_state-context, vars)) {
ret = compute_mst_dsc_configs_for_state(state, dm_state-context, vars);
if (ret) {DRM_DEBUG_DRIVER("compute_mst_dsc_configs_for_state()
failed\n");
ret = -EINVAL; goto fail; }diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 6ff96b4bdda5c..bba2e8aaa2c20 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -703,13 +703,13 @@ static int bpp_x16_from_pbn(struct dsc_mst_fairness_params param, int pbn) return dsc_config.bits_per_pixel; }
-static bool increase_dsc_bpp(struct drm_atomic_state *state,
struct drm_dp_mst_topology_state *mst_state,struct dc_link *dc_link,struct dsc_mst_fairness_params *params,struct dsc_mst_fairness_vars *vars,int count,int k)+static int increase_dsc_bpp(struct drm_atomic_state *state,
struct drm_dp_mst_topology_state *mst_state,struct dc_link *dc_link,struct dsc_mst_fairness_params *params,struct dsc_mst_fairness_vars *vars,int count,int k){ int i; bool bpp_increased[MAX_PIPES]; @@ -719,6 +719,7 @@ static bool increase_dsc_bpp(struct drm_atomic_state *state, int remaining_to_increase = 0; int link_timeslots_used; int fair_pbn_alloc;
int ret = 0;
for (i = 0; i < count; i++) { if (vars[i + k].dsc_enabled) {
@@ -757,52 +758,60 @@ static bool increase_dsc_bpp(struct drm_atomic_state *state,
if (initial_slack[next_index] > fair_pbn_alloc) { vars[next_index].pbn += fair_pbn_alloc;
if (drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn) < 0)
return false;if (!drm_dp_mst_atomic_check(state)) {
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn);
if (ret < 0)return ret;ret = drm_dp_mst_atomic_check(state);if (ret == 0) { vars[next_index].bpp_x16 =bpp_x16_from_pbn(params[next_index], vars[next_index].pbn); } else { vars[next_index].pbn -= fair_pbn_alloc;
if (drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn) < 0)
return false;
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn);
if (ret < 0)return ret; } } else { vars[next_index].pbn += initial_slack[next_index];
if (drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn) < 0)
return false;if (!drm_dp_mst_atomic_check(state)) {
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn);
if (ret < 0)return ret;ret = drm_dp_mst_atomic_check(state);if (ret == 0) { vars[next_index].bpp_x16 =params[next_index].bw_range.max_target_bpp_x16; } else { vars[next_index].pbn -= initial_slack[next_index];
if (drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn) < 0)
return false;
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn);
if (ret < 0)return ret; } } bpp_increased[next_index] = true; remaining_to_increase--;}
- return true;
- return 0;
}
-static bool try_disable_dsc(struct drm_atomic_state *state,
struct dc_link *dc_link,struct dsc_mst_fairness_params *params,struct dsc_mst_fairness_vars *vars,int count,int k)+static int try_disable_dsc(struct drm_atomic_state *state,
struct dc_link *dc_link,struct dsc_mst_fairness_params *params,struct dsc_mst_fairness_vars *vars,int count,int k){ int i; bool tried[MAX_PIPES]; @@ -810,6 +819,7 @@ static bool try_disable_dsc(struct drm_atomic_state *state, int max_kbps_increase; int next_index; int remaining_to_try = 0;
int ret;
for (i = 0; i < count; i++) { if (vars[i + k].dsc_enabled
@@ -840,49 +850,52 @@ static bool try_disable_dsc(struct drm_atomic_state *state, break;
vars[next_index].pbn =kbps_to_peak_pbn(params[next_index].bw_range.stream_kbps);
if (drm_dp_atomic_find_time_slots(state,params[next_index].port-mgr,
params[next_index].port,vars[next_index].pbn) < 0)return false;
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port-mgr,
params[next_index].port,vars[next_index].pbn);if (ret < 0)return ret;
if (!drm_dp_mst_atomic_check(state)) {
ret = drm_dp_mst_atomic_check(state);if (ret == 0) { vars[next_index].dsc_enabled = false; vars[next_index].bpp_x16 = 0; } else { vars[next_index].pbn =kbps_to_peak_pbn(params[next_index].bw_range.max_kbps);
if (drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn) < 0)
return false;
ret = drm_dp_atomic_find_time_slots(state,params[next_index].port->mgr,
params[next_index].port,
vars[next_index].pbn);
if (ret < 0)return ret; } tried[next_index] = true; remaining_to_try--;}
- return true;
- return 0;
}
-static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dc_link *dc_link,struct dsc_mst_fairness_vars *vars,struct drm_dp_mst_topology_mgr*mgr,
int *link_vars_start_index)+static int compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dc_link *dc_link,struct dsc_mst_fairness_vars *vars,struct drm_dp_mst_topology_mgr*mgr,
int *link_vars_start_index){ struct dc_stream_state *stream; struct dsc_mst_fairness_params params[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; struct drm_dp_mst_topology_state *mst_state = drm_atomic_get_mst_topology_state(state, mgr); int count = 0;
- int i, k;
int i, k, ret; bool debugfs_overwrite = false;
memset(params, 0, sizeof(params));
if (IS_ERR(mst_state))
return false;
return PTR_ERR(mst_state);mst_state->pbn_div = dm_mst_get_pbn_divider(dc_link); #if
defined(CONFIG_DRM_AMD_DC_DCN) @@ -933,7 +946,7 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state,
if (count == 0) { ASSERT(0);
return true;
return 0;}
/* k is start index of vars for current phy link used by mst hub */ @@
-947,13 +960,17 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.stream_kbps); vars[i + k].dsc_enabled = false; vars[i + k].bpp_x16 = 0;
if (drm_dp_atomic_find_time_slots(state, params[i].port-mgr, params[i].port,
vars[i + k].pbn) < 0)return false;
ret = drm_dp_atomic_find_time_slots(state, params[i].port-mgr, params[i].port,
vars[i + k].pbn);if (ret < 0)return ret;
- if (!drm_dp_mst_atomic_check(state) && !debugfs_overwrite) {
- ret = drm_dp_mst_atomic_check(state);
- if (ret == 0 && !debugfs_overwrite) { set_dsc_configs_from_fairness_vars(params, vars, count, k);
return true;
return 0;} else if (ret != -ENOSPC) {
return ret;}
/* Try max compression */
@@ -962,31 +979,36 @@ static bool compute_mst_dsc_configs_for_link(struct drm_atomic_state *state, vars[i + k].pbn = kbps_to_peak_pbn(params[i].bw_range.min_kbps); vars[i + k].dsc_enabled = true; vars[i + k].bpp_x16 = params[i].bw_range.min_target_bpp_x16;
if (drm_dp_atomic_find_time_slots(state,params[i].port->mgr,
params[i].port, vars[i
- k].pbn) < 0)
return false;
ret = drm_dp_atomic_find_time_slots(state,params[i].port->mgr,
params[i].port,vars[i + k].pbn);
if (ret < 0)return ret; } else { vars[i + k].pbn =kbps_to_peak_pbn(params[i].bw_range.stream_kbps); vars[i + k].dsc_enabled = false; vars[i + k].bpp_x16 = 0;
if (drm_dp_atomic_find_time_slots(state,params[i].port->mgr,
params[i].port, vars[i
- k].pbn) < 0)
return false;
ret = drm_dp_atomic_find_time_slots(state,params[i].port->mgr,
params[i].port,vars[i + k].pbn);
if (ret < 0)return ret; }
- if (drm_dp_mst_atomic_check(state))
return false;
ret = drm_dp_mst_atomic_check(state);
if (ret != 0)
return ret;/* Optimize degree of compression */
- if (!increase_dsc_bpp(state, mst_state, dc_link, params, vars, count,
k))
return false;
- ret = increase_dsc_bpp(state, mst_state, dc_link, params, vars,
count, k);
- if (ret < 0)
return ret;
- if (!try_disable_dsc(state, dc_link, params, vars, count, k))
return false;
ret = try_disable_dsc(state, dc_link, params, vars, count, k);
if (ret < 0)
return ret;set_dsc_configs_from_fairness_vars(params, vars, count, k);
- return true;
- return 0;
}
static bool is_dsc_need_re_compute( @@ -1087,15 +1109,16 @@ static bool is_dsc_need_re_compute( return is_dsc_need_re_compute; }
-bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars *vars)+int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars *vars){ int i, j; struct dc_stream_state *stream; bool computed_streams[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; int link_vars_start_index = 0;
int ret = 0;
for (i = 0; i < dc_state->stream_count; i++) computed_streams[i] = false;
@@ -1118,17 +1141,19 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state, continue;
if (dcn20_remove_stream_from_ctx(stream->ctx->dc,dc_state, stream) != DC_OK)
return false;
return -EINVAL; if (!is_dsc_need_re_compute(state, dc_state, stream->link)) continue; mutex_lock(&aconnector->mst_mgr.lock);
if (!compute_mst_dsc_configs_for_link(state, dc_state,stream->link, vars,
&aconnector->mst_mgr,&link_vars_start_index)) {
ret = compute_mst_dsc_configs_for_link(state, dc_state,stream->link, vars,
&aconnector->mst_mgr,&link_vars_start_index);if (ret != 0) { mutex_unlock(&aconnector->mst_mgr.lock);
return false;
return ret; } mutex_unlock(&aconnector->mst_mgr.lock);@@ -1143,22 +1168,22 @@ bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
if (stream->timing.flags.DSC == 1) if (dc_stream_add_dsc_to_resource(stream->ctx-dc, dc_state, stream) != DC_OK)
return false;
return -EINVAL;
- return true;
- return ret;
}
-static bool
- pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state
*state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars*vars) +static int pre_compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars*vars) { int i, j; struct dc_stream_state *stream; bool computed_streams[MAX_PIPES]; struct amdgpu_dm_connector *aconnector; int link_vars_start_index = 0;
int ret;
for (i = 0; i < dc_state->stream_count; i++) computed_streams[i] = false;
@@ -1184,11 +1209,12 @@ static bool continue;
mutex_lock(&aconnector->mst_mgr.lock);
if (!compute_mst_dsc_configs_for_link(state, dc_state,stream->link, vars,
&aconnector->mst_mgr,&link_vars_start_index)) {
ret = compute_mst_dsc_configs_for_link(state, dc_state,stream->link, vars,
&aconnector->mst_mgr,&link_vars_start_index);if (ret != 0) { mutex_unlock(&aconnector->mst_mgr.lock);
return false;
return ret; } mutex_unlock(&aconnector->mst_mgr.lock);@@ -1198,7 +1224,7 @@ static bool } }
- return true;
- return ret;
}
static int find_crtc_index_in_state_by_stream(struct drm_atomic_state *state, @@ -1253,9 +1279,9 @@ static bool is_dsc_precompute_needed(struct drm_atomic_state *state) return ret; }
-bool pre_validate_dsc(struct drm_atomic_state *state,
struct dm_atomic_state **dm_state_ptr,struct dsc_mst_fairness_vars *vars)+int pre_validate_dsc(struct drm_atomic_state *state,
struct dm_atomic_state **dm_state_ptr,struct dsc_mst_fairness_vars *vars){ int i; struct dm_atomic_state *dm_state; @@ -1264,11 +1290,12 @@ bool pre_validate_dsc(struct drm_atomic_state *state,
if (!is_dsc_precompute_needed(state)) { DRM_INFO_ONCE("DSC precompute is not needed.\n");
return true;
return 0;
- if (dm_atomic_get_state(state, dm_state_ptr)) {
- ret = dm_atomic_get_state(state, dm_state_ptr);
- if (ret != 0) { DRM_INFO_ONCE("dm_atomic_get_state() failed\n");
return false;
return ret;@@ -1280,7 +1307,7 @@ bool pre_validate_dsc(struct drm_atomic_state *state,
local_dc_state = kmemdup(dm_state->context, sizeof(structdc_state), GFP_KERNEL); if (!local_dc_state)
return false;
return -ENOMEM;for (i = 0; i < local_dc_state->stream_count; i++) { struct dc_stream_state *stream = dm_state->context-
streams[i]; @@ -1316,9 +1343,9 @@ bool pre_validate_dsc(struct
drm_atomic_state *state, if (ret != 0) goto clean_exit;
- if (!pre_compute_mst_dsc_configs_for_state(state, local_dc_state,
vars)) {
- ret = pre_compute_mst_dsc_configs_for_state(state, local_dc_state,
vars);
if (ret != 0) {
DRM_INFO_ONCE("pre_compute_mst_dsc_configs_for_state()
failed\n");
ret = -EINVAL; goto clean_exit;@@ -1349,7 +1376,7 @@ bool pre_validate_dsc(struct drm_atomic_state *state,
kfree(local_dc_state);
- return (ret == 0);
- return ret;
}
static unsigned int kbps_from_pbn(unsigned int pbn) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h index b92a7c5671aa2..97fd70df531bf 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h @@ -53,15 +53,15 @@ struct dsc_mst_fairness_vars { struct amdgpu_dm_connector *aconnector; };
-bool compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars *vars);+int compute_mst_dsc_configs_for_state(struct drm_atomic_state *state,
struct dc_state *dc_state,struct dsc_mst_fairness_vars *vars);bool needs_dsc_aux_workaround(struct dc_link *link);
-bool pre_validate_dsc(struct drm_atomic_state *state,
struct dm_atomic_state **dm_state_ptr,struct dsc_mst_fairness_vars *vars);+int pre_validate_dsc(struct drm_atomic_state *state,
struct dm_atomic_state **dm_state_ptr,struct dsc_mst_fairness_vars *vars);enum dc_status dm_dp_mst_is_port_support_mode( struct amdgpu_dm_connector *aconnector, -- 2.37.3
-- Cheers, Lyude Paul (she/her) Software Engineer at Red Hat