Re: patch acpi-ec-allow-multibyte-access-to-ec.patch added to 2.6.33-stabletree

[Stefan Bader]

gregkh@xxxxxxx wrote:
> This is a note to let you know that we have just queued up the patch titled
> 
>     Subject: ACPI: EC: Allow multibyte access to EC
> 
> to the 2.6.33-stable tree.  Its filename is
> 
>     acpi-ec-allow-multibyte-access-to-ec.patch
> 
> A git repo of this tree can be found at 
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> 
> From ben@xxxxxxxxxxxxxxx  Wed Apr 21 12:11:57 2010
> From: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
> Date: Sat, 10 Apr 2010 02:18:35 +0100
> Subject: ACPI: EC: Allow multibyte access to EC
> To: stable@xxxxxxxxxx
> Cc: Len Brown <len.brown@xxxxxxxxx>, 563313@xxxxxxxxxxxxxxx, Alexey Starikovskiy <astarikovskiy@xxxxxxx>
> Message-ID: <1270862315.2176.69.camel@localhost>
> 
> 
> From: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
> 
> commit dadf28a10c3eb29421837a2e413ab869ebd upstream
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=14667
> 
> [bwh: Backport to 2.6.32; same applies to 2.6.33]
> 
> Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
> Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
> Cc: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
> 
> ---
>  drivers/acpi/acpica/exprep.c |   12 ++++++++++++
>  drivers/acpi/ec.c            |   35 +++++++++--------------------------
>  2 files changed, 21 insertions(+), 26 deletions(-)
> 
> --- a/drivers/acpi/acpica/exprep.c
> +++ b/drivers/acpi/acpica/exprep.c
> @@ -468,6 +468,18 @@ acpi_status acpi_ex_prep_field_value(str
>  
>  		acpi_ut_add_reference(obj_desc->field.region_obj);
>  
> +		/* allow full data read from EC address space */
> +		if (obj_desc->field.region_obj->region.space_id ==
> +			ACPI_ADR_SPACE_EC) {
> +			if (obj_desc->common_field.bit_length > 8)
> +				obj_desc->common_field.access_bit_width =
> +				ACPI_ROUND_UP(obj_desc->common_field.
> +							bit_length, 8);
> +				obj_desc->common_field.access_byte_width =
> +				ACPI_DIV_8(obj_desc->common_field.
> +							access_bit_width);
> +		}
> +
>  		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
>  				  "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
>  				  obj_desc->field.start_field_bit_offset,
> --- a/drivers/acpi/ec.c
> +++ b/drivers/acpi/ec.c
> @@ -589,12 +589,12 @@ static u32 acpi_ec_gpe_handler(void *dat
>  
>  static acpi_status
>  acpi_ec_space_handler(u32 function, acpi_physical_address address,
> -		      u32 bits, acpi_integer *value,
> +		      u32 bits, acpi_integer *value64,
>  		      void *handler_context, void *region_context)
>  {
>  	struct acpi_ec *ec = handler_context;
> -	int result = 0, i;
> -	u8 temp = 0;
> +	int result = 0, i, bytes = bits / 8;
> +	u8 *value = (u8 *)value64;
>  
>  	if ((address > 0xFF) || !value || !handler_context)
>  		return AE_BAD_PARAMETER;
> @@ -602,32 +602,15 @@ acpi_ec_space_handler(u32 function, acpi
>  	if (function != ACPI_READ && function != ACPI_WRITE)
>  		return AE_BAD_PARAMETER;
>  
> -	if (bits != 8 && acpi_strict)
> -		return AE_BAD_PARAMETER;
> -
> -	if (EC_FLAGS_MSI)
> +	if (EC_FLAGS_MSI || bits > 8)
>  		acpi_ec_burst_enable(ec);
>  
> -	if (function == ACPI_READ) {
> -		result = acpi_ec_read(ec, address, &temp);
> -		*value = temp;
> -	} else {
> -		temp = 0xff & (*value);
> -		result = acpi_ec_write(ec, address, temp);
> -	}
> -
> -	for (i = 8; unlikely(bits - i > 0); i += 8) {
> -		++address;
> -		if (function == ACPI_READ) {
> -			result = acpi_ec_read(ec, address, &temp);
> -			(*value) |= ((acpi_integer)temp) << i;
> -		} else {
> -			temp = 0xff & ((*value) >> i);
> -			result = acpi_ec_write(ec, address, temp);
> -		}
> -	}
> +	for (i = 0; i < bytes; ++i, ++address, ++value)
> +		result = (function == ACPI_READ) ?
> +			acpi_ec_read(ec, address, value) :
> +			acpi_ec_write(ec, address, *value);
>  
> -	if (EC_FLAGS_MSI)
> +	if (EC_FLAGS_MSI || bits > 8)
>  		acpi_ec_burst_disable(ec);
>  
>  	switch (result) {
> 
> 
> Patches currently in stable-queue which might be from astarikovskiy@xxxxxxx are
> 
> queue-2.6.33/acpi-ec-allow-multibyte-access-to-ec.patch
> --
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Hi Greg,

make sure to also pick the following one as it fixes a regression caused by the
mulitbyte access patch.

commit 2060c44576c79086ff24718878d7edaa7384a985
Author: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
Date:   Fri Apr 16 15:36:40 2010 -0400

    ACPI: EC: Limit burst to 64 bits

-Stefan
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