Hello Yihe,
We are using Transparency Key , Global Alpha Blending and Partial Alpha Blending through FBDev IOCTLS.
However we find that sometimes enabling/disabling the Global/Partial Alpha Blending or the Transparency Key has no effect. This issue occurs about 20% of the time.
We are using the following version of FBDev
- HDVPSS.01.00.01.25
- TI814X-LINUX-PSP-04.01.00.01 (Linux 2.6.34 kernel)
We have a test application that enables/disables Global Alpha Blending through command line argument.
We follow the following steps to recreate the problem.
(a) Enable Global Alpha Blending to make entire screen Transparent.
(b) Disable Global Alpha Blending to make entire screen Opaque.
(c) Go back to step (a)
Repeat step (a) -> (b) -> (c) for 15 to 20 times; you may find that after step (a) the screen may not be transparent.
At this point if you repeat step (a) multiple times you will find that the screen shall become transparent.
Similarly this problem may occur after step (b).
Also this issue occurs with Transparency Keying, Global Alpha Blending and Partial Alpha Blending.
We have tried the following to debug the problem
- We have tried reading back the Transparency & Alpha Blending values using TIFB_GET_PARAMS to see if the changes are applied. We find that the values read back as expected.
- We connected the JTAG to the M3 and read the registers 0x48105108 to 0x48105114 and find that they are always 0x0. (Reference: DM814x_HDVPSS_Advanced_Information_Document.pdf). Are these registers correct ? Which registers are being used to configure the Alpha Blending and Transparency ?
Have you come across such issues ?
regards,
Sami Mujawar