+Doug Hello, AFAIR, dw_mmc host controller does support UHS-I [1], specially SDR50 and SDR104 modes. [1]: http://www.spinics.net/lists/linux-mmc/msg28186.html What I remember is, one need to set "broken-cd" property also in order to make it work because of the vqmmc and vmmc connection on board. I didn't find the link right now, but you can search on the web, there was a long discussion about handling this. Have not checked it recently, so not sure if this got broken somehow. Regards, Alim On Wed, Oct 14, 2015 at 5:29 AM, Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> wrote: > On 14.10.2015 01:27, Anand Moon wrote: >> 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. > > Nope, that did not answer my query. You gave some performance benchmarks > but my question was not about the speed of anything. The question is > (once again): > How do you know that these modes are really supported? > > You are marking the *host* as supporting these modes. Please provide > information that host supports them *really*, not by experimenting "oh, > it seems to work now, maybe it will work always". > > Usually vendors, if their products implement some kind of > specification/protocol, they mark the products as "compatible with XYZ" etc. > > Best regards, > Krzysztof > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Regards, Alim -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
