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From: Catalin Marinas <catalin.marinas@arm.com>
To: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Sibi Sankar <quic_sibis@quicinc.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	amit.pundir@linaro.org, andersson@kernel.org,
	sumit.semwal@linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()"
Date: Thu, 1 Dec 2022 17:45:43 +0000	[thread overview]
Message-ID: <Y4joR2sQMMjIt+yE@arm.com> (raw)
In-Reply-To: <6d637906-e1d5-c481-a73d-2b2b845e223b@leemhuis.info>

On Thu, Dec 01, 2022 at 10:29:39AM +0100, Thorsten Leemhuis wrote:
> Has any progress been made to fix this regression? It afaics is not a
> release critical issue, but well, it still would be nice to get this
> fixed before 6.1 is released.

The only (nearly) risk-free "fix" for 6.1 would be to revert the commit
that exposed the driver bug. It doesn't fix the actual bug, it only
makes it less likely to happen.

I like the original commit removing the cache invalidation as it shows
drivers not behaving properly but, as a workaround, we could add a
command line option to force back the old behaviour (defaulting to the
new one) until the driver is fixed.

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Sibi Sankar <quic_sibis@quicinc.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	amit.pundir@linaro.org, andersson@kernel.org,
	sumit.semwal@linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()"
Date: Thu, 1 Dec 2022 17:45:43 +0000	[thread overview]
Message-ID: <Y4joR2sQMMjIt+yE@arm.com> (raw)
In-Reply-To: <6d637906-e1d5-c481-a73d-2b2b845e223b@leemhuis.info>

On Thu, Dec 01, 2022 at 10:29:39AM +0100, Thorsten Leemhuis wrote:
> Has any progress been made to fix this regression? It afaics is not a
> release critical issue, but well, it still would be nice to get this
> fixed before 6.1 is released.

The only (nearly) risk-free "fix" for 6.1 would be to revert the commit
that exposed the driver bug. It doesn't fix the actual bug, it only
makes it less likely to happen.

I like the original commit removing the cache invalidation as it shows
drivers not behaving properly but, as a workaround, we could add a
command line option to force back the old behaviour (defaulting to the
new one) until the driver is fixed.

-- 
Catalin

  reply	other threads:[~2022-12-01 17:56 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14 11:03 [PATCH] Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()" Manivannan Sadhasivam
2022-11-14 11:03 ` Manivannan Sadhasivam
2022-11-14 11:29 ` Manivannan Sadhasivam
2022-11-14 11:29   ` Manivannan Sadhasivam
2022-11-14 14:11 ` Will Deacon
2022-11-14 14:11   ` Will Deacon
2022-11-14 15:14   ` Robin Murphy
2022-11-14 15:14     ` Robin Murphy
2022-11-14 17:38     ` Catalin Marinas
2022-11-14 17:38       ` Catalin Marinas
2022-11-18 10:54       ` Manivannan Sadhasivam
2022-11-18 10:54         ` Manivannan Sadhasivam
2022-11-18 12:33         ` Will Deacon
2022-11-18 12:33           ` Will Deacon
2022-11-21  6:42           ` Manivannan Sadhasivam
2022-11-21  6:42             ` Manivannan Sadhasivam
2022-11-21 10:12             ` Sibi Sankar
2022-11-21 10:12               ` Sibi Sankar
2022-11-24 11:55               ` Catalin Marinas
2022-11-24 11:55                 ` Catalin Marinas
2022-12-01  9:29                 ` Thorsten Leemhuis
2022-12-01  9:29                   ` Thorsten Leemhuis
2022-12-01 17:45                   ` Catalin Marinas [this message]
2022-12-01 17:45                     ` Catalin Marinas
2022-12-02  8:26                     ` Amit Pundir
2022-12-02  8:26                       ` Amit Pundir
2022-12-02  8:54                       ` Thorsten Leemhuis
2022-12-02  8:54                         ` Thorsten Leemhuis
2022-12-02 10:03                         ` Will Deacon
2022-12-02 10:03                           ` Will Deacon
2022-12-02 10:34                           ` Thorsten Leemhuis
2022-12-02 10:34                             ` Thorsten Leemhuis
2022-12-02 16:10                             ` Greg KH
2022-12-02 16:10                               ` Greg KH
2022-12-02 16:27                               ` Thorsten Leemhuis
2022-12-02 16:27                                 ` Thorsten Leemhuis
2022-12-02 16:32                                 ` Greg KH
2022-12-02 16:32                                   ` Greg KH
2022-12-02 17:14                                   ` Manivannan Sadhasivam
2022-12-02 17:14                                     ` Manivannan Sadhasivam
2022-12-05 14:24                                     ` Will Deacon
2022-12-05 14:24                                       ` Will Deacon
2022-12-06  9:21                                       ` Manivannan Sadhasivam
2022-12-06  9:21                                         ` Manivannan Sadhasivam
2022-12-06  9:58                                         ` Will Deacon
2022-12-06  9:58                                           ` Will Deacon
2022-12-02 10:54                           ` Manivannan Sadhasivam
2022-12-02 10:54                             ` Manivannan Sadhasivam
2022-11-28  5:44 ` Thorsten Leemhuis
2022-11-28  5:44   ` Thorsten Leemhuis
2022-11-28  8:15   ` Manivannan Sadhasivam
2022-11-28  8:15     ` Manivannan Sadhasivam
2022-12-08  4:59 ` Leonard Lausen
2022-12-08  4:59   ` Leonard Lausen
  -- strict thread matches above, loose matches on Subject: below --
2022-12-06 10:34 Will Deacon
2022-12-06 11:24 ` Manivannan Sadhasivam
2022-12-06 17:50 ` Catalin Marinas

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