Messages in this thread |  | | Date | Sun, 17 Apr 2022 21:53:23 +0800 | Subject | Re: [PATCH] dmaengine: pl330: Fix unbalanced runtime PM | From | sugar zhang <> |
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Hi Vinod,
在 2022/4/11 21:48, Vinod Koul 写道: > On 26-03-22, 20:16, Sugar Zhang wrote: >> 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(force) > maybe unconditional is a better word than force here? okay, will do in v2. > >> | | >> >> 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: >> commit 5c9e6c2b2ba3 ("dmaengine: pl330: Fix runtime PM support for terminated transfers") >> commit ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12") > That is not the right way for Fixes tag
like this?
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> >> --- >> >> drivers/dma/pl330.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> 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 */ >> -- >> 2.7.4
-- Best Regards! 张学广/Sugar 瑞芯微电子股份有限公司 Rockchip Electronics Co., Ltd.
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