i.MX6Q/DL Lowering power consumption in suspend mode

[steveectype]

There should be a quick and easy optimisation when screen suspension occurs. The IPU suspension control should eventually reach the function:

void mx6q_ipuv3_pg(int enable) { /*TODO*/ }

However it hasn't been implemented and there seems to be a large chunk of the BSP missing; although there are examples for i.MX53 and i.MX51 the part for i.MX6 is missing.

See Android BSP imx-android-13.4.1

./kernel_imx/arch/arm/plat-mxc/devices/platform-imx_ipuv3.c

There does seem to be a small amount of documentation in the Reference Manual (page 1348), but none of the PG memory map exists in the source code BSP. This part is weakly supported. Is ther any help the community can give on this problem?

Although the documentation on i.MX 6Dual/6Quad Power Consumption Management (rev0) suggests that "Futher optimisations are planned to be implemented in future BSP releases...". Surely I am not the only person who needs low power consumption when in suspend mode?

[AnsonHuang · Accepted solution]

Hi, Steve

     For this suspend power, do you mean the system suspend or just IPU suspend? If only for IPU suspend, which is mapped to the system idle mode of our BSP, the internal BUS freq will be set to lower setpoint, it will save many power, but I don't think there is much that IPU drivers need to do under this mode. As on i.MX6 series SOCs, IPU didn't have its own power gating, its power is from SOC which can NOT be off, so we didn't need to do that in this mx6q_ipuv3_pg routine. But for i.MX5, there should be PU gating that can be done when IPU is suspended.

     So, different power tree design cause different operation of IPU driver, this routine is there only for software compatible, it will do nothing on i.MX6Q.