Re: [PATCH for-5.1] acpi: allow accessing acpi-cnt register by byte

[Michael S. Tsirkin]

On Mon, Jul 20, 2020 at 06:39:15PM +0300, Michael Tokarev wrote:
> >From the ACPI spec (4.8.3.2.1 PM1 Control Registers):
> 
> Register Location: <PM1a_CNT_BLK / PM1b_CNT_BLK> System I/O or Memory Space
> Default Value:     00h
> Attribute:         Read/Write
> Size:              PM1_CNT_LEN (2 bytes)
> The PM1 control registers contain the fixed hardware feature control bits.
> These bits can be split between two registers: PM1a_CNT or PM1b_CNT.
> Each register grouping can be at a different 32-bit aligned address
> and is pointed to by the PM1a_CNT_BLK or PM1b_CNT_BLK. The values
> for these pointers to the register space are found in the FADT.
> Accesses to PM1 control registers are accessed through byte
> and word accesses.
> 
> So allow 1-byte access too, not only 2-byte.
> 
> Fixes: afafe4bbe0cf7d3318e1ac7b40925561f86a6bd4
> Fixes: 5d971f9e672507210e77d020d89e0e89165c8fc9

Fixes links are a bit off. Should be:
Fixes: <short sha> ("commit subject")

> Buglink: 
> https://lore.kernel.org/xen-devel/20200630170913.123646-1-anthony.perard@citrix.com/T/
> Buglink: https://bugs.debian.org/964793
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  hw/acpi/core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index f6d9ec4f13..2c1199d9dc 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -599,7 +599,8 @@ static void acpi_pm_cnt_write(void *opaque, hwaddr addr, 
> uint64_t val,
>  static const MemoryRegionOps acpi_pm_cnt_ops = {
>      .read = acpi_pm_cnt_read,
>      .write = acpi_pm_cnt_write,
> -    .valid.min_access_size = 2,
> +    .impl.min_access_size = 2,
> +    .valid.min_access_size = 1,
>      .valid.max_access_size = 2,
>      .endianness = DEVICE_LITTLE_ENDIAN,
>  };
> -- 
> 2.20.1