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[91.155.111.71]) by smtp.gmail.com with ESMTPSA id a25sm2254255lfl.38.2021.05.18.04.36.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 May 2021 04:36:30 -0700 (PDT) Subject: Re: [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors To: Tony Lindgren , Vinod Koul Cc: dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, Aaro Koskinen , Adam Ford , Andreas Kemnade References: <20210518074347.16908-1-tony@atomide.com> From: =?UTF-8?Q?P=c3=a9ter_Ujfalusi?= Message-ID: Date: Tue, 18 May 2021 14:36:29 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210518074347.16908-1-tony@atomide.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 18/05/2021 10:43, Tony Lindgren wrote: > There's no need to restore DMA context on CPU_CLUSTER_PM_ENTER_FAILED as > the DMA context won't be lost on errors. > > Note that this does not cause invalid context restore as we already check > for busy DMA with omap_dma_busy() in CPU_CLUSTER_PM_ENTER, and block any > deeper idle states for the SoC by returning NOTIFY_BAD if busy. > > If other drivers block deeper idle states with cpu_pm, we now just do a > pointless restore, but only if dma was not busy on CPU_CLUSTER_PM_ENTER. > > Let's update the CPU_CLUSTER_PM_ENTER_FAILED handling for correctness, > and add a comment. Make sense, Acked-by: Peter Ujfalusi > Cc: Aaro Koskinen > Cc: Adam Ford > Cc: Andreas Kemnade > Cc: Peter Ujfalusi > Signed-off-by: Tony Lindgren > --- > drivers/dma/ti/omap-dma.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c > --- a/drivers/dma/ti/omap-dma.c > +++ b/drivers/dma/ti/omap-dma.c > @@ -1608,7 +1608,8 @@ static int omap_dma_context_notifier(struct notifier_block *nb, > return NOTIFY_BAD; > omap_dma_context_save(od); > break; > - case CPU_CLUSTER_PM_ENTER_FAILED: > + case CPU_CLUSTER_PM_ENTER_FAILED: /* No need to restore context */ > + break; > case CPU_CLUSTER_PM_EXIT: > omap_dma_context_restore(od); > break; > -- Péter