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SubjectRe: I2C block reads with i2c-viapro: testers wanted
Jean Delvare wrote:
>
> Could you try running "i2cdump 0 0x50" and "i2cdump 0 0x50 i" (with the
> patch still applied), and compare both the outputs and the time each
> command takes? You should see similar outputs, but the second command
> should be magnitudes faster. This would confirm that the I2C block mode
> works as intended on your VT8233 chip.

Hmm, not really. Here it takes 6 seconds for the first test nad about 5 seconds
for the second test (I just read the WARNING - need to substract 5s from the
results...).

noa xtrm # time i2cdump 0 0x50
No size specified (using byte-data access)
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0, address 0x50, mode byte
You have five seconds to reconsider and press CTRL-C!

0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 80 08 07 0d 09 02 40 00 04 75 75 00 82 10 00 01 ??????@.?uu.??.?
10: 0e 04 0c 01 02 20 00 a0 75 00 00 50 3c 50 2d 20 ????? .?u..P<P-
20: 90 90 50 50 00 00 00 00 00 00 00 00 00 00 00 00 ??PP............
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a7 ...............?
40: ce 00 00 00 00 00 00 00 01 4d 34 20 37 30 4c 33 ?.......?M4 70L3
50: 32 32 34 44 54 30 2d 43 42 30 20 30 44 02 51 45 224DT0-CB0 0D?QE
60: 0b c8 db 00 4c 39 41 37 43 33 4e 00 00 00 00 00 ???.L9A7C3N.....
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: 00 20 12 02 22 07 ff ff ff ff ff 18 04 16 ff ff . ??"?.....???..
90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................

real 0m6.033s
user 0m0.000s
sys 0m0.004s
noa xtrm # time i2cdump 0 0x50 i
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0, address 0x50, mode i2c block
You have five seconds to reconsider and press CTRL-C!

0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 80 08 07 0d 09 02 40 00 04 75 75 00 82 10 00 01 ??????@.?uu.??.?
10: 0e 04 0c 01 02 20 00 a0 75 00 00 50 3c 50 2d 20 ????? .?u..P<P-
20: 90 90 50 50 00 00 00 00 00 00 00 00 00 00 00 00 ??PP............
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a7 ...............?
40: ce 00 00 00 00 00 00 00 01 4d 34 20 37 30 4c 33 ?.......?M4 70L3
50: 32 32 34 44 54 30 2d 43 42 30 20 30 44 02 51 45 224DT0-CB0 0D?QE
60: 0b c8 db 00 4c 39 41 37 43 33 4e 00 00 00 00 00 ???.L9A7C3N.....
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: 00 20 12 02 22 07 ff ff ff ff ff 18 04 16 ff ff . ??"?.....???..
90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................

real 0m5.174s
user 0m0.001s
sys 0m0.002s

while simple cat takes a lot less time:
noa xtrm # time dd if=/sys/bus/i2c/devices/0-0050/eeprom bs=4 | hexdump -C
00000000 80 08 07 0d 09 02 40 00 04 75 75 00 82 10 00 01 |......@..uu.....|
00000010 0e 04 0c 01 02 20 00 a0 75 00 00 50 3c 50 2d 20 |..... ..u..P<P- |
00000020 90 90 50 50 00 00 00 00 00 00 00 00 00 00 00 00 |..PP............|
00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a7 |................|
00000040 ce 00 00 00 00 00 00 00 01 4d 34 20 37 30 4c 33 |.........M4 70L3|
00000050 32 32 34 44 54 30 2d 43 42 30 20 30 44 02 51 45 |224DT0-CB0 0D.QE|
00000060 0b c8 db 00 4c 39 41 37 43 33 4e 00 00 00 00 00 |....L9A7C3N.....|
00000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000080 00 20 12 02 22 07 ff ff ff ff ff 18 04 16 ff ff |. .."...........|
00000090 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
*
64+0 zapisov na vhodu
64+0 zapisov na izhodu
00000100

real 0m0.600s
user 0m0.002s
sys 0m0.005s

It seems pretty fast in all cases (i2cdump, i2cdump block and cat) and results
are close too (taing WARNING delay into account).

regards,
hinko k
--
..because under Linux "if something is possible in principle,
then it is already implemented or somebody is working on it".

--LKI
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