Post
Topic
Board Mining (Altcoins)
Re: Antminer D3 Blissz firmware (20/11 update available!)
by
peeter
on 20/11/2017, 23:27:35 UTC
The D3 cgminer driver (released by Bitmain) doesn't even mention X11 or subalgorithms. You can check:


There is struct work_dash that contains interesting type field. However it has fixed unknown value 0x20.

Code:
   
struct work_dash
{
    uint8_t type;                           // Bit[7:5]: Type,fixed as 0x01. Bit[4]:sno valid   Bit[3:0]:reserved
    uint8_t wc;                             // bit[7]: reserved, bit[6:0]: work count base
    uint8_t work[WORK_DATA_INPUT_LENGTH];   // 0-75 bytes are dash work; 76-79 are start nonce field
    uint16_t crc16;                         // crc, but not include the header 0x55, 0xaa
};
//...

// BM1760 ASIC input data length
#define WORK_INPUT_TYPE_WITH_SNO                    0x30
#define WORK_INPUT_TYPE_WITHOUT_SNO                 0x20

//...

void *DASH_fill_work(void *usrdata)
{
struct work_dash workdata;
//...
workdata.type = WORK_INPUT_TYPE_WITHOUT_SNO;
//...
DASH_write(info->dev_fd[chainid], (uint8_t *)&workdata, WORK_INPUT_LENGTH_WITH_CRC);


It would be interesting to fuzz work_dash.type a bit, to see if BM1760 supports some other types. However probably this wouldn't do anything useful.

So IMHO this means unless there is secret golden switch inside chip BM1760, there is no way to choose algorithm.
BM1760 is Bitmain private chip. There is no public spec available, all they say about it is "BM1760 custom-made chip using 28nm technology."  Wink