Hi Krzysztof,
On 13 October 2015 at 09:13, Krzysztof Kozlowski
<k.kozlowski@xxxxxxxxxxx> wrote:
>
> On 13.10.2015 12:08, Anand Moon wrote:
> > Hi Krzysztof,
> >
> > On 13 October 2015 at 05:44, Krzysztof Kozlowski
> > <k.kozlowski@xxxxxxxxxxx> wrote:
> >> On 13.10.2015 00:32, Anand Moon wrote:
> >>> Hi Krzysztof,
> >>>
> >>> On 12 October 2015 at 11:14, Krzysztof Kozlowski
> >>> <k.kozlowski@xxxxxxxxxxx> wrote:
> >>>> On 12.10.2015 00:46, Anand Moon wrote:
> >>>>> Added support for UHS-I bus speed 50MB/s (SDR50, DDR50) 104MB/s (SDR104)
> >>>>
> >>>> This description is not entirely correct. The MMC driver already
> >>>> supports these UHS speeds (you did not any code) so you rather enabled
> >>>> it (description of bindings says "is supported").
> >>>>
> >>>> You mentioned DDR50 but I don't see respective property below.
> >>>>
> >>>> How do you know that these modes are really supported? I don't know. Can
> >>>> you convince me?
> >>>
> >>> Setting this DDR50 capability give me this error. That's the reason to
> >>> drop this capability.
> >>
> >> But you mentioned it in commit message! "Added support for UHS-I ...
> >> (DDR50)"
> >>
> >> In the same time dropping DDR50 is not an sufficient proof that "SDR50
> >> and SDR104 are really supported".
> >>
> >
> > These changes are related to the microSD card capabilities.
> > So SDR50 have better frequency over DDR50. On the same Sandisk card.
> >
> > When the card select the capability for DDR50
> > ---------------------------------------------------
> > [ 4.001477] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot
> > req 50000000Hz, actual 50000000HZ div = 0)
> > [ 4.001604] mmc1: new ultra high speed DDR50 SDHC card at address aaaa
> > [ 4.004505] mmcblk0: mmc1:aaaa SL32G 29.7 GiB
> > [ 4.009179] mmcblk0: error -110 sending status command, retrying
> > [ 4.009271] mmcblk0: error -115 sending stop command, original cmd
> > response 0x900, card status 0x900
> > [ 4.009275] mmcblk0: error -84 transferring data, sector 0, nr 8,
> > cmd response 0x900, card status 0x0
> > [ 4.025563] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot
> > req 400000Hz, actual 396825HZ div = 63)
> > [ 4.067770] Console: switching to colour frame buffer device 274x77
> > [ 4.098782] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot
> > req 50000000Hz, actual 50000000HZ div = 0)
> > [ 4.099692] mmc1: tried to reset card
> > [ 4.101332] mmcblk0: p1 p2
> >
> >
> > When the card select the capability for SDR50
> > ---------------------------------------------------------------------------------
> > [ 2.439806] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req
> > 100000000Hz, actual 100000000HZ div = 0)
> > [ 2.449729] mmc1: new ultra high speed SDR50 SDHC card at address aaaa
> > [ 2.455984] mmcblk0: mmc1:aaaa SL32G 29.7 GiB
> > [ 2.461743] mmcblk0: p1 p2
> >
> > Which will relate to better read/write speed.
>
> Which is not an answer to my question. To none of my previous questions.
>
Basically UHS-I capability (sd-uhs-sdr12, sd-uhs-sdr25, sd-uhs-sdr50,
sd-uhs-sdr104) help tune speed supported for mmc
I have tired to compare the speed on high speed UHS-I vs ultra high
speed UHS-I using izone utility.
[ 2.572469] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot
req 50000000Hz, actual 50000000HZ div = 0)
[ 2.572609] mmc1: new high speed SDHC card at address aaaa
Command line used: ./iozone -L64 -S32 -azecwI -+n -r4k -r64k
-r128k -s10M -i0 -i1 -i2 -f datafile -Rb out.xls
Output is in kBytes/sec
Time Resolution = 0.000001 seconds.
Processor cache size set to 32 kBytes.
Processor cache line size set to 64 bytes.
File stride size set to 17 * record size.
random
random bkwd record stride
kB reclen write rewrite read reread read
write read rewrite read fwrite frewrite fread
freread
10240 4 1631 0 6556 0 5538 982
10240 64 8828 0 18897 0 17994 303
10240 128 6269 0 20670 0 20128 1096
---------------------------------------------------------------------------------------------------------
[ 2.613761] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot
req 100000000Hz, actual 100000000HZ div = 0)
[ 2.623573] mmc1: new ultra high speed SDR50 SDHC card at address aaaa
Command line used: ./iozone -L64 -S32 -azecwI -+n -r4k -r64k
-r128k -s10M -i0 -i1 -i2 -f datafile -Rb out.xls
Output is in kBytes/sec
Time Resolution = 0.000001 seconds.
Processor cache size set to 32 kBytes.
Processor cache line size set to 64 bytes.
File stride size set to 17 * record size.
random
random bkwd record stride
kB reclen write rewrite read reread read
write read rewrite read fwrite frewrite fread
freread
10240 4 1809 0 7507 0 5233 859
10240 64 11622 0 31250 0 28072 516
10240 128 4320 0 34417 0 32509 1148
My observation is that their slight increase in read/write operation.
Hope I have tried to answer you query. If I am wrong please let me know.
-Anand Moon
>
> Best regards,
> Krzysztof
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