CRITICALITY

High

DESCRIPTION

LCD1 output supports gamma correction. The color look-up table (CLUT) is shared between the BITMAP to RGB conversion module on GFX pipeline and Gamma correction on the LCD1 output. LUT table can be loaded by SW through DISPC slave port (interconnect) or by DISPC master port using the DISPC DMA.

However, LCD1 gamma correction LUT loading is not working properly and require to enable GFX pipeline for LUT loading. Depending on the load mode (DISPC_CONFIG1[2:1] LOADMODE) used, GFX pipeline can then be disabled after 1st frame.

WORKAROUND

WA1

To use gamma correction on LCD1 output, software must:

1. Enable the GFX pipeline by setting DISPC_GFX_ATTRIBUTES[0] ENABLE to 0x1.
2. Set the GFX base address (DISPC_GFX_BA_i[31:0] BA) to an accessible frame buffer.
3. Set the GFX window to minimum size by configuring the DISPC_GFX_SIZE[27:16] SIZEY and DISPC_GFX_SIZE[10:0] SIZEX bits.
4. If the GFX pipeline is not to be displayed, set GFX LYR to bottom LYR in LCD1 overlay by setting appropriate DISPC_GFX_ATTRIBUTES[27:26] ZORDER bit field and make GFX fully transparent by setting the global alpha of the GFX to 0x00 in the DISPC_GLOBAL_ALPHA[7:0] GFXGLOBALALPHA bit field.

REVISIONS IMPACTED

AM574x SR 1.0
AM576x SR 1.0

AM574x: 1.0

DRA75xP, DRA74xP, DRA77xP, DRA76xP: 1.0

TDA2Px: 1.0

AM576x: 1.0