Re: [Qemu-devel] [PATCH] fix acpi regression

[Wen Congyang <wency@cn.fujitsu.com>]

At 04/12/2011 05:20 PM, Isaku Yamahata Write:
> On Tue, Apr 12, 2011 at 05:08:18PM +0800, Wen Congyang wrote:
>> At 04/12/2011 04:48 PM, Isaku Yamahata Write:
>>> On Tue, Apr 12, 2011 at 01:13:15PM +0800, Wen Congyang wrote:
>>>> This bug is introduced by commit 23910d3f.
>>>
>>> Oh, Thanks. Good catch. I agree with the first hunk.
>>> But what is the second hunk for? The GPE STS register is W1C.
>>> (NULL check and 0xff masking is okay. it's a bit redundant, though)
>>
>> I found this bug when I hotplug a nic.
>> I do not know about ACPI.
>> The second hunk is the same before commit 23910d3f.
>> I will read ACPI spec to confirm it and update this patch.
> 
> You mean gpe_writeb(), gpe_write_val(), gpe_reset_val()?
> gpe_reset_val() does W1C.
> The GPE0_LEN of piix4 is 4 byte length and the first 2 registers are
> sts register. From the old code,
> 
> static void gpe_reset_val(uint16_t *cur, int addr, uint32_t val)
> {   
>     uint16_t x1, x0 = val & 0xff;
>     int shift = (addr & 1) ? 8 : 0;
> 
>     x1 = (*cur >> shift) & 0xff;
> 
>     x1 = x1 & ~x0; <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< W1C
> 
>     *cur = (*cur & (0xff << (8 - shift))) | (x1 << shift);
> }
> 
> 
> static void gpe_writeb(void *opaque, uint32_t addr, uint32_t val)
> {   
>     PIIX4PMState *s = opaque;
>     struct gpe_regs *g = &s->gpe;
> 
>     switch (addr) {
>         case GPE_BASE:
>         case GPE_BASE + 1:
>             gpe_reset_val(&g->sts, addr, val);
>             break;

Ah, you are right.
Thanks.

> 
> thanks,
> 
>>
>> Thanks
>>
>>>
>>> >From ACPI4 spec 4.7.4.1.1.
>>> can only be cleared by software writing a "1" to its respective bit position.
>>>
>>> thanks,
>>>
>>>>
>>>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>>>>
>>>> ---
>>>>  hw/acpi.c |   10 +++-------
>>>>  1 files changed, 3 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/hw/acpi.c b/hw/acpi.c
>>>> index e372474..790bd3b 100644
>>>> --- a/hw/acpi.c
>>>> +++ b/hw/acpi.c
>>>> @@ -355,7 +355,7 @@ static uint8_t *acpi_gpe_ioport_get_ptr(ACPIGPE *gpe, uint32_t addr)
>>>>      if (addr < gpe->len / 2) {
>>>>          cur = gpe->sts + addr;
>>>>      } else if (addr < gpe->len) {
>>>> -        cur = gpe->en + addr;
>>>> +        cur = gpe->en + addr - gpe->len / 2;
>>>>      } else {
>>>>          abort();
>>>>      }
>>>> @@ -369,12 +369,8 @@ void acpi_gpe_ioport_writeb(ACPIGPE *gpe, uint32_t addr, uint32_t val)
>>>>  
>>>>      addr -= gpe->blk;
>>>>      cur = acpi_gpe_ioport_get_ptr(gpe, addr);
>>>> -    if (addr < gpe->len / 2) {
>>>> -        /* GPE_STS */
>>>> -        *cur = (*cur) & ~val;
>>>> -    } else if (addr < gpe->len) {
>>>> -        /* GPE_EN */
>>>> -        *cur = val;
>>>> +    if (cur != NULL) {
>>>> +        *cur = val & 0xff;
>>>>      } else {
>>>>          abort();
>>>>      }
>>>> -- 
>>>> 1.7.1
>>>>
>>
>>
>