Received-SPF: pass (google.com: domain of linux-kernel+bounces-193559-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Feedback-ID: i56a14606:Fastmail
User-Agent: Cyrus-JMAP/3.11.0-alpha0-491-g033e30d24-fm-20240520.001-g033e30d2
Precedence: bulk
MIME-Version: 1.0
Message-Id: <fcbdc4a5-abee-4de8-9fe8-c8486195b96d@app.fastmail.com>
In-Reply-To: 
 <DM4PR11MB5995875EEC9ACCFC43D8B86A93F22@DM4PR11MB5995.namprd11.prod.outlook.com>
References: <20240528115802.3122955-1-arnd@kernel.org>
 <DM4PR11MB5995875EEC9ACCFC43D8B86A93F22@DM4PR11MB5995.namprd11.prod.outlook.com>
Date: Wed, 29 May 2024 09:06:17 +0200
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Lixu Zhang" <lixu.zhang@intel.com>, "Arnd Bergmann" <arnd@kernel.org>,
 "srinivas.pandruvada@linux.intel.com" <srinivas.pandruvada@linux.intel.com>,
 "Jiri Kosina" <jikos@kernel.org>, "Benjamin Tissoires" <bentiss@kernel.org>
Cc: "linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] HID: intel-ish-hid: fix cache management mistake
Content-Type: text/plain

On Wed, May 29, 2024, at 08:46, Zhang, Lixu wrote:
>>
>>-#include <linux/cacheflush.h>
>> #include <linux/container_of.h>
>> #include <linux/dev_printk.h>
>> #include <linux/dma-mapping.h>
>>@@ -175,10 +174,11 @@ static int prepare_dma_bufs(struct ishtp_device
>>*dev,
>> 			return -ENOMEM;
>>
>> 		fragment->fragment_tbl[i].ddr_adrs =
>>cpu_to_le64(dma_addr);
>>+
>>+		memcpy(dma_bufs[i], ish_fw->data + offset, fragment-
>>>fragment_tbl[i].length);
> fragment->fragment_tbl[i].length was used before assignment.
> 
>>+		dma_wmb();
> I tested it on the platform, but it didn't wok.
>

What behavior do you see instead? If the manual cache
flush works around a bug, that would indicate that the
device itself is not coherent and the dma_alloc_coherent()
in the architecture is broken.

     Arnd