[PATCH 2/2] drm/nouveau/clk: only update clk->pstate after hardware programming succeeds

Francesco Magazzu <[email protected]> Mon, 27 Jul 2026 17:28:21 +0200
Newsgroups org.freedesktop.lists.nouveau,org.freedesktop.lists.dri-devel,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
nvkm_pstate_prog() wrote clk->pstate = pstatei before attempting the RAM
and core clock reprogramming. If either step failed, the software state
tracker had already committed to the new pstate even though the hardware
transition never completed, and a later re-request for that same state
could be skipped (pstate != clk->pstate would be false), leaving the
hardware stuck out of sync with what the driver believes it's running.

Move the assignment to after nvkm_cstate_prog() returns, and only commit
it on success.

Found by Sashiko AI review (https://sashiko.dev) while reviewing
"[PATCH v2 2/4] drm/nouveau/clk: don't use the pstate cursor after the
loop" ([email protected]) as a
pre-existing issue.

Signed-off-by: Francesco Magazzu <[email protected]>
---
 nvkm/subdev/clk/base.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/nvkm/subdev/clk/base.c b/nvkm/subdev/clk/base.c
index 737bec8..91c51d4 100644
--- a/nvkm/subdev/clk/base.c
+++ b/nvkm/subdev/clk/base.c
@@ -285,7 +285,6 @@ nvkm_pstate_prog(struct nvkm_clk *clk, int pstatei)
 		return -EINVAL;
 
 	nvkm_debug(subdev, "setting performance state %d\n", pstatei);
-	clk->pstate = pstatei;
 
 	nvkm_pcie_set_link(pci, pstate->pcie_speed, pstate->pcie_width);
 
@@ -302,7 +301,11 @@ nvkm_pstate_prog(struct nvkm_clk *clk, int pstatei)
 			return ret;
 	}
 
-	return nvkm_cstate_prog(clk, pstate, NVKM_CLK_CSTATE_HIGHEST);
+	ret = nvkm_cstate_prog(clk, pstate, NVKM_CLK_CSTATE_HIGHEST);
+	if (ret == 0)
+		clk->pstate = pstatei;
+
+	return ret;
 }
 
 static void
-- 
2.55.0