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iMX6SLL-EVK SDIO 3.0 interface WiFi throughput is less

Question asked by Pandi Vijayaraj on Jun 15, 2018
Latest reply on Jun 20, 2018 by Pandi Vijayaraj

Hi All,


I am interfacing an external WiFi module card supporting SDIO 3.0 with IMX6SLL-EVK host platform. IMX6SLL-EVK host is running Linux kernel 4.9.11 and driver is inserted properly into the kernel. The SDIO port used is uSDHC3.

I am attaching here the dmesg MMC logs during bootup with the WiFI card inserted

The SDIO port sattus information is given below.

               ubuntu@arm:~$ sudo cat /sys/kernel/debug/mmc2/ios
               clock: 208000000 Hz
               actual clock: 198000000 Hz
               vdd: 18 (3.0 ~ 3.1 V)
               bus mode: 2 (push-pull)
               chip select: 0 (don't care)
               power mode: 2 (on)
               bus width: 2 (4 bits)
               timing spec: 6 (sd uhs SDR104)
               signal voltage: 1 (1.80 V)
               driver type: 0 (driver type B)


I believe that WiFi card is detected in UHS SDR104 mode. But when I test WiFi transmit throughput, It is around 100Mbps only. It is similar to the SDIO 2.0 mode throughput observed in some laptop hosts.

I expect the transmit throughput to be more than atleast 200Mbps.

Is there any limitation in iMX6SLL-EVK performace. pls, let me know the problem in this scenario.

Also suggest some platforms supporting high throughput in SDIO 3.0 mode.



Pandi Vijayaraj