From 85c323c3e89d6e1b624b839c3325ae072952e545 Mon Sep 17 00:00:00 2001 From: Debarshi Dutta Date: Wed, 8 Aug 2018 17:36:01 +0530 Subject: gpu: nvgpu: restrict devfreq during active clk_arb set requests Restrict access to devfreq when there are active set requests in the clk_arbiter. We make the following changes in the patch. 1) Add a global counter in the struct gk20a named clk_arb_global_nr which is used to track the number of active set requests in the system. 2) Anytime a set request is successfully made by the userspace, clk_arb_global_nr is incremented by 1 and during the completion of request(releasing the corresponding file handle), clk_arb_global_nr is decremented by 1. 3) gk20a_scale_target(invoked by devfreq to set the new frequency based on load) atomically checks clk_arb_global_nr. If the value = 0, the code simply continue or else if its > 0, it quits thus making devfreq requests mutually exclusive with the clk_arbiter. Bug 2061372 Change-Id: I5d19de03e45520f4ff8fccb97b1f1589d04c8ab8 Signed-off-by: Debarshi Dutta Reviewed-on: https://git-master.nvidia.com/r/1790002 Reviewed-by: mobile promotions Tested-by: mobile promotions --- drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c') diff --git a/drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c b/drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c index 2d9946b1..ff1cc00a 100644 --- a/drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c +++ b/drivers/gpu/nvgpu/os/linux/ioctl_clk_arb.c @@ -436,6 +436,7 @@ int nvgpu_clk_arb_commit_request_fd(struct gk20a *g, clk_arb_dbg(g, "requested target = %u\n", (u32)dev->gpc2clk_target_mhz); + nvgpu_atomic_inc(&g->clk_arb_global_nr); nvgpu_ref_get(&dev->refcount); nvgpu_spinlock_acquire(&session->session_lock); nvgpu_list_add(&dev->node, &session->targets); -- cgit v1.2.2