Sample depth texture Mali-400

Hi Mali devs,

We are working on an android game that perform depth texture to implement post-process effect, like fog of war. We sample depth texture and convert it into world space to do some calculation to achieve a final UV, and then use this UV to sample another texture that store fog of war data, the result is good on Qualcomm devices with Adreno320 GPU, but wrong on Mali-400.

If we ignore other steps, only sample depth texture and linearize it, it looks incorrect (banding...), some devs thinks this is a precision issue, is it true? if it's a precision problem, are there any solution to solve this problem.

Thanks.