Re: [PATCH i-g-t v2 1/4] lib/gppgu_shader: Add write D32 to ppgtt virtual address

[Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>]

On 11/22/24 12:47 PM, Hajda, Andrzej wrote:
> 
>>>> +{
>>>> +    uint64_t addr = CANONICAL(ppgtt_addr);
>>>> +    igt_assert_f((addr & 0x3) == 0, "address must be aligned to 
>>>> DWord!\n");
>>>> +
>>>> +    emit_iga64_code(shdr, write_a64_dword, " \n\
>>>> +#if GEN_VER >= 2000                                \n\
>>>> +// Unyped 2D Block Store                            \n\
>>>> +// Instruction_Store2DBlock                            \n\
>>>> +// bspec: 63981                                    \n\
>>>> +// src0 address payload (Untyped2DBLOCKAddressPayload) specifies 
>>>> both        \n\
>>>> +//    the block parameters and the 2D Surface 
>>>> parameters.            \n\
>>>> +// src1 data payload format is selected by Data 
>>>> Size.                \n\
>>>> +// Untyped2DBLOCKAddressPayload \n\
>>>> +// bspec: 63986                                    \n\
>>>> +// [243:240] Array Length: 0 (length is 1) \n\
>>>> +// [239:232] Block Height: 0 (height is 1) \n\
>>>> +// [231:224] Block Width: 0xf (width is 16)                    \n\
>>>> +// [223:192] Block Start Y: 0                            \n\
>>>> +// [191:160] Block Start X: 0                            \n\
>>>> +// [159:128] Untyped 2D Surface Pitch: 0x3f (pitch is 64 
>>>> bytes)            \n\
>>>> +// [127:96] Untyped 2D Surface Height: 0 (height is 
>>>> 1)                \n\
>>>> +// [95:64] Untyped 2D Surface Width: 0x3f (width is 64 
>>>> bytes)            \n\
>>>> +// [63:0] Untyped 2D Surface Base Address \n\
>>>> +// initialize register                                \n\
>>>> +(W)    mov (8)            r30.0<1>:uq 0x0:uq                \n\
>>>> +// [0:31] Untyped 2D Surface Base Address low                    \n\
>>>> +(W)    mov (1)            r30.0<1>:ud ARG(0):ud            \n\
>>>> +// [32:63] Untyped 2D Surface Base Address high                    \n\
>>>> +(W)    mov (1)            r30.1<1>:ud ARG(1):ud                \n\
>>>> +// [95:64] Untyped 2D Surface Width: 0x3f \n\
>>>> +//       (Width minus 1 (in bytes) of the 2D surface, it represents 
>>>> 64)    \n\
>>>> +(W)    mov (1)         r30.2<1>:ud 0x3f:ud                \n\
>>>> +// [127:96] Untyped 2D Surface Height: 0x0 \n\
>>>> +//        (Height minus 1 (in number of data elements) 
>>>> of            \n\
>>>> +//        the Untyped 2D surface, it represents 1)                \n\
>>>> +(W)    mov (1)         r30.3<1>:ud 0x0:ud                \n\
>>>> +// [159:128] Untyped 2D Surface Pitch: 0x3f                    \n\
>>>> +//         (Pitch minus 1 (in bytes) of the 2D surface, it 
>>>> represents 64)    \n\
>>>> +(W)    mov (1)            r30.4<1>:ud 0x3f:ud                \n\
>>>> +// [231:224] Block Width: 0xf (15)                        \n\
>>>> +//         (Specifies the width minus 1 (in number of data 
>>>> elements) for this    \n\
>>>> +//         rectangular region, it represents 16)                \n\
>>>> +// Block width (encoded_value + 1) must be a multiple of DW (4 
>>>> bytes).        \n\
>>>> +// [239:232] Block Height: 0                            \n\
>>>> +//         (Specifies the height minus 1 (in number of data 
>>>> elements) for    \n\
>>>> +//         this rectangular region, it represents 1) \n\
>>>> +// [243:240] Array Length: 0                            \n\
>>>> +//         (Specifies Array Length minus 1 for Load2DBlockArray 
>>>> messages,    \n\
>>>> +//         must be zero for 2D Block Store messages, it represents 
>>>> 1)        \n\
>>>> +(W)    mov (1)            r30.7<1>:ud 0xf:ud                \n\
>>>
>>>
>>> Shouldn't this be 0x3:ud now, for dword ?
>>>
>> No, r30.7 needs to set 0xf:ud.
> 
> 
> 0xf mean block width is 16 bytes, it means 4 dwords, in the description 
> you says one d32,
> 
> to source register r31 you enter also d32, and zeroes the rest.
> 
> So what is going here? Writing one dword, or 4dwords (one provided, and 
> the rest 0) ?
> 
Good catch.
Yes it should be changed to use 1 dword from 4dwords as you commented.
I'll update both read and write functions.

Thanks!

G.G.