On 18 December 2015 at 04:05, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote: > On 2015/12/18 9:28, Jaehoon Chung wrote: >> >> Hi, >> >> On 12/18/2015 06:49 AM, Ulf Hansson wrote: >>> >>> On 17 December 2015 at 20:47, Alan Cooper <alcooperx@xxxxxxxxx> wrote: >>>> >>>> On Wed, Dec 16, 2015 at 4:07 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> >>>> wrote: >>>>> >>>>> To find the improved card detection times, I just used the kernel boot >>>>> log and checked the time stamps for when the cards get detected. I ran >>>>> the tests ~10 times and picked up some average values. >>>>> >>>>> To notice the improvement you need at least two cards to be inserted >>>>> during boot. Perhaps you have a platform with one eMMC and one SD card >>>>> slot, you can test. >>>> >>>> >>>> I tested the patch on one of our ARM bases SoC's. The SoC has an SD >>>> card slot on the first controller and an eMMC device on the second >>>> controller. I found ~100ms improvement on the time it took for the >>>> rootfs on the eMMC device to be ready for use. Interestingly, I did >>>> see the SD/eMMC order swap once in 20 tries. This is not an issue for >>>> us as we already have to use UUID for the eMMC rootfs in case an SD >>>> card is installed. >>>> > Hi Shawn, Thanks for helping out testing. > hi Ulf, > I'm interested in this patch since I also spent a little time optimzing > the boot time and sequence for my local branch based on kernel 3.1x. With > you patch, it seems, the tablet only achieves very small improvement for the > SD controller(less than 20ms). > > My test environment: > Kernel: 3.14 > Slot: 1 emmc(1st) + 1 SD card(2nd) + 1 sdio card(3rd) How much time you *gain* comparing to the original behaviour for each card, depends on the ->probe() order of your mmc hosts. I would guess that the host that holds the eMMC is the one being probed first, right? In general eMMC is quite fast to initialize, comparing to SD-cards and that's probably the reason to why you don't see that much improvements. Although, for your SDIO card you should see a greater improvement as this don't need to wait for your SD and eMMC to be initialized. > > I happen to run massive reboot test for my stable kernel branch this > weekend, so I will apply this patch to see if any problem occurs. :) > Great! As you haven't reported any problems, I suppose the tests went well!? Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
