| Message ID | 1650450456-34351-1-git-send-email-sugar.zhang@rock-chips.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [v2] dmaengine: pl330: Fix unbalanced runtime PM | expand |
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 858400e..ccd430e 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2084,7 +2084,7 @@ static void pl330_tasklet(struct tasklet_struct *t) spin_lock(&pch->thread->dmac->lock); _stop(pch->thread); spin_unlock(&pch->thread->dmac->lock); - power_down = true; + power_down = pch->active; pch->active = false; } else { /* Make sure the PL330 Channel thread is active */
This driver use runtime PM autosuspend mechanism to manager clk. pm_runtime_use_autosuspend(&adev->dev); pm_runtime_set_autosuspend_delay(&adev->dev, PL330_AUTOSUSPEND_DELAY); So, after ref count reached to zero, it will enter suspend after the delay time elapsed. The unbalanced PM: * May cause dmac the next start failed. * May cause dmac read unexpected state. * May cause dmac stall if power down happen at the middle of the transfer. e.g. may lose ack from AXI bus and stall. Considering the following situation: DMA TERMINATE TASKLET ROUTINE | | | issue_pending | | | pch->active = true | pm_runtime_get pm_runtime_put(if active) | pch->active = false | | work_list empty | | | pm_runtime_put(unconditional) | | At this point, it's unbalanced(1 get / 2 put). After this patch: DMA TERMINATE TASKLET ROUTINE | | | issue_pending | | | pch->active = true | pm_runtime_get pm_runtime_put(if active) | pch->active = false | | work_list empty | | | pm_runtime_put(if active) | | Now, it's balanced(1 get / 1 put). Fixes: 5c9e6c2b2ba3 ("dmaengine: pl330: Fix runtime PM support for terminated transfers") Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12") Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com> Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com> --- Changes in v2: - fixup commit message per Vinod suggestion. drivers/dma/pl330.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)