Mesa (staging/20.2): radeonsi: fix a nasty bug in si_pm4.c

[GitLab Mirror]

Module: Mesa
Branch: staging/20.2
Commit: cd94b261fc3eeebea0db69af6ba6811e650de0bb
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=cd94b261fc3eeebea0db69af6ba6811e650de0bb

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Sun Nov 22 23:19:44 2020 -0500

radeonsi: fix a nasty bug in si_pm4.c

If you did:
  si_pm4_set_reg(pm4, reg, val0);
  si_pm4_cmd_add(pm4, val1);
  si_pm4 set_reg(pm4, reg + 4, val1);

it wrote val0 to reg, val1 to reg + 4, and val2 to reg + 8.

This fixes it by clearing last_opcode in si_pm4_cmd_add, so that
si_pm4_set_reg doesn't try to combine set_reg calls across si_pm4_cmd_add.

Fixes: da78d50bc87 - radeonsi: make si_pm4_cmd_begin/end static and simplify all usages

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7721>
(cherry picked from commit 0d4f1dcd155be753ff49cd763be916cf701cda25)

---

 .pick_status.json                     | 2 +-
 src/gallium/drivers/radeonsi/si_pm4.c | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 5d31550846c..bd8f38e9542 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -958,7 +958,7 @@
         "description": "radeonsi: fix a nasty bug in si_pm4.c",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": "da78d50bc87ef5db846a942664094b6299cd1888"
     },
diff --git a/src/gallium/drivers/radeonsi/si_pm4.c b/src/gallium/drivers/radeonsi/si_pm4.c
index d1d003af1d4..e4ddbc8d59b 100644
--- a/src/gallium/drivers/radeonsi/si_pm4.c
+++ b/src/gallium/drivers/radeonsi/si_pm4.c
@@ -38,6 +38,7 @@ void si_pm4_cmd_add(struct si_pm4_state *state, uint32_t dw)
 {
    assert(state->ndw < SI_PM4_MAX_DW);
    state->pm4[state->ndw++] = dw;
+   state->last_opcode = -1;
 }
 
 static void si_pm4_cmd_end(struct si_pm4_state *state, bool predicate)
@@ -76,13 +77,15 @@ void si_pm4_set_reg(struct si_pm4_state *state, unsigned reg, uint32_t val)
 
    reg >>= 2;
 
+   assert(state->ndw + 2 <= SI_PM4_MAX_DW);
+
    if (opcode != state->last_opcode || reg != (state->last_reg + 1)) {
       si_pm4_cmd_begin(state, opcode);
-      si_pm4_cmd_add(state, reg);
+      state->pm4[state->ndw++] = reg;
    }
 
    state->last_reg = reg;
-   si_pm4_cmd_add(state, val);
+   state->pm4[state->ndw++] = val;
    si_pm4_cmd_end(state, false);
 }