linux-kernel - Re: [PATCH v2 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values

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Message-ID: <ec91a9ff-7c64-4428-b32d-c65d7a5a1ed3@gmx.de>
Date: Fri, 8 Mar 2024 17:04:49 +0100
From: Armin Wolf <W_Armin@....de>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Hans de Goede <hdegoede@...hat.com>, "Rafael J. Wysocki"
 <rafael@...nel.org>, lenb@...nel.org, linux-acpi@...r.kernel.org,
 platform-driver-x86@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] platform/x86: wmi: Support reading/writing 16 bit
 EC values

Am 08.03.24 um 09:01 schrieb Ilpo Järvinen:

> On Thu, 7 Mar 2024, Armin Wolf wrote:
>
>> The ACPI EC address space handler currently only supports
>> reading/writing 8 bit values. Some firmware implementations however
>> want to access for example 16 bit values, which is prefectly legal
>> according to the ACPI spec.
>>
>> Add support for reading/writing such values.
>>
>> Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.
>>
>> Signed-off-by: Armin Wolf <W_Armin@....de>
>> @@ -1162,27 +1188,28 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
>>   			  u32 bits, u64 *value,
>>   			  void *handler_context, void *region_context)
>>   {
>> -	int result = 0;
>> -	u8 temp = 0;
>> +	int bytes = bits / BITS_PER_BYTE;
>> +	int ret;
>> +
>> +	if (!value)
>> +		return AE_NULL_ENTRY;
>>
>> -	if ((address > 0xFF) || !value)
>> +	if (bytes > sizeof(*value))
>>   		return AE_BAD_PARAMETER;
>>
>> -	if (function != ACPI_READ && function != ACPI_WRITE)
>> +	if (address > U8_MAX || address + bytes > U8_MAX)
> This doesn't look correct. With address = 0xff and bits = 8 this will
> return AE_BAD_PARAMETER, is that intensional?
>
You are absolutely correct, i will send an updated series soon.

Thanks,
Armin Wolf