On mainboards with analog VGA output the memory size is incorrectly
detected due to an invalid register probe. This leads to a corrupted
and unusable framebuffer on the analog VGA output.
Do not probe the DP501-related VGA scratch register if the DP501
device was not detected.
Tested-on: ASUS KGPE-D16 (AST2050) w/ 8MB VRAM.
Signed-off-by: Timothy Pearson <tpearson@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/ast/ast_main.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 7bc3aa6..090b571 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -372,17 +372,19 @@ static u32 ast_get_vram_info(struct drm_device *dev)
case 3: vram_size = AST_VIDMEM_SIZE_64M; break;
}
- jreg = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0x99, 0xff);
- switch (jreg & 0x03) {
- case 1:
- vram_size -= 0x100000;
- break;
- case 2:
- vram_size -= 0x200000;
- break;
- case 3:
- vram_size -= 0x400000;
- break;
+ if (ast->tx_chip_type == AST_TX_DP501) {
+ jreg = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0x99, 0xff);
+ switch (jreg & 0x03) {
+ case 1:
+ vram_size -= 0x100000;
+ break;
+ case 2:
+ vram_size -= 0x200000;
+ break;
+ case 3:
+ vram_size -= 0x400000;
+ break;
+ }
}
return vram_size;
--
2.8.1
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