The Aspeed ast drm driver has the frame-buffer RGBX swapped on
big-endian RISC systems. Fix by enabling byte swapping for any
__BIG_ENDIAN config.
Fixes: 12fec1405dd5 ("drm: Initial KMS driver for AST (ASpeed Technologies)
2000 series (v2)")
Signed-off-by: René Rebe <[email protected]>
---
Tested on Oracle T4-1 running sparc64 T2/Linux.
---
drivers/gpu/drm/ast/ast_mode.c | 14 ++++++++++++++
drivers/gpu/drm/ast/ast_reg.h | 6 ++++++
2 files changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 30b011ed0a05..155ae35470d9 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -708,6 +708,20 @@ static void ast_crtc_helper_mode_set_nofb(struct drm_crtc
*crtc)
ast_set_dclk_reg(ast, adjusted_mode, vmode);
ast_set_crtthd_reg(ast);
ast_set_sync_reg(ast, adjusted_mode, vmode);
+
+#ifdef __BIG_ENDIAN
+ /* Big-endian byte-swapping */
+ switch (ast_crtc_state->format->format) {
+ case DRM_FORMAT_RGB565:
+ ast_set_index_reg_mask(ast, AST_IO_VGACRI, AST_IO_VGACRA2,
0x3f, 0x40);
+ break;
+ case DRM_FORMAT_XRGB8888:
+ ast_set_index_reg_mask(ast, AST_IO_VGACRI, AST_IO_VGACRA2,
0x3f, 0x80);
+ break;
+ default:
+ break;
+ }
+#endif
}
static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
diff --git a/drivers/gpu/drm/ast/ast_reg.h b/drivers/gpu/drm/ast/ast_reg.h
index 30578e3b07e4..5c8c0fd2e229 100644
--- a/drivers/gpu/drm/ast/ast_reg.h
+++ b/drivers/gpu/drm/ast/ast_reg.h
@@ -75,4 +75,10 @@
#define AST_IO_VGAIR1_R (0x5A)
#define AST_IO_VGAIR1_VREFRESH BIT(3)
+/*
+ * PCI Control
+ */
+
+#define AST_IO_VGACRA2 (0xA2) /* PCI control & big-endian */
+
#endif
--
2.52.0
--
René Rebe, ExactCODE GmbH, Berlin, Germany
https://exactco.de • https://t2linux.com • https://patreon.com/renerebe
