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Message-ID: <ff852f4a-7d37-c947-139d-8882a3ebb9a3@huawei.com>
Date:   Thu, 10 Nov 2022 20:08:25 +0800
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Subject: Re: [PATCH 2/3] ACPI: PCC: add check for platform interrupt
To:     Sudeep Holla <sudeep.holla@arm.com>
CC:     <linux-acpi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <rafael@kernel.org>, <rafael.j.wysocki@intel.com>,
        <wanghuiqiang@huawei.com>, <zhangzekun11@huawei.com>,
        <wangxiongfeng2@huawei.com>, <tanxiaofei@huawei.com>,
        <guohanjun@huawei.com>, <xiexiuqi@huawei.com>,
        <wangkefeng.wang@huawei.com>, <huangdaode@huawei.com>
References: <20221110015034.7943-1-lihuisong@huawei.com>
 <20221110015034.7943-3-lihuisong@huawei.com>
 <20221110103618.3vuyfdhcebf7ewmo@bogus>
From:   "lihuisong (C)" <lihuisong@huawei.com>
In-Reply-To: <20221110103618.3vuyfdhcebf7ewmo@bogus>
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在 2022/11/10 18:36, Sudeep Holla 写道:
> On Thu, Nov 10, 2022 at 09:50:33AM +0800, Huisong Li wrote:
>> PCC Operation Region driver senses the completion of command by interrupt
>> way. If platform can not generate an interrupt when a command complete,
>> the caller never gets the desired result. So let's reject the setup of the
>> PCC address space on platform that do not support interrupt mode.
>>
>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>> ---
>>   drivers/acpi/acpi_pcc.c | 47 +++++++++++++++++++++++++----------------
>>   1 file changed, 29 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c
>> index 3e252be047b8..8efd08e469aa 100644
>> --- a/drivers/acpi/acpi_pcc.c
>> +++ b/drivers/acpi/acpi_pcc.c
>> @@ -53,6 +53,7 @@ acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
>>   	struct pcc_data *data;
>>   	struct acpi_pcc_info *ctx = handler_context;
>>   	struct pcc_mbox_chan *pcc_chan;
>> +	static acpi_status ret;
>>   
>>   	data = kzalloc(sizeof(*data), GFP_KERNEL);
>>   	if (!data)
>> @@ -69,23 +70,35 @@ acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
>>   	if (IS_ERR(data->pcc_chan)) {
>>   		pr_err("Failed to find PCC channel for subspace %d\n",
>>   		       ctx->subspace_id);
>> -		kfree(data);
>> -		return AE_NOT_FOUND;
>> +		ret = AE_NOT_FOUND;
>> +		goto request_channel_fail;
>>   	}
>>
> Your patch seems to be not based on the upstream.
> Commit f890157e61b8 ("ACPI: PCC: Release resources on address space setup
> failure path") has addressed it already.
I make this patch based on the commit f890157e61b8.
Here is to unify the relese resources path.
>
>>   	pcc_chan = data->pcc_chan;
>> +	if (!pcc_chan->mchan->mbox->txdone_irq) {
>> +		pr_err("This channel-%d does not support interrupt.\n",
>> +		       ctx->subspace_id);
>> +		ret = AE_SUPPORT;
>> +		goto request_channel_fail;
>> +	}
> Indeed, I supported only interrupt case and this approach is better than
> checking it in handler atleast until we add support for polling based
> transfers in future(hope that never happens, but you never know)
Yes
>