From 67e9cbb66be47fd2aeadd2ad91fe15e076340140 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Thu, 18 Sep 2025 09:50:28 +0200 Subject: [PATCH] ast: Use VGACR17 sync enable and VGASR01 screen disable Blank the display by disabling sync pulses with VGACR17<7>. Some BMC's don't handle VGACRB6 correctly. Keep the change to VGASR1's SD bit, as some BMCs disable GPU access to VRAM. --- drivers/gpu/drm/ast/ast_mode.c | 18 ++++++++++-------- drivers/gpu/drm/ast/ast_reg.h | 1 + 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index 6b9d510c509d..8e3d56798e9e 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -836,22 +836,24 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc, static void ast_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state) { struct ast_device *ast = to_ast_device(crtc->dev); + u8 vgacr17 = 0x00; + u8 vgasr01 = 0x00; - ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, 0x00); - ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0x00); + vgacr17 |= AST_IO_VGACR17_SYNC_ENABLE; + vgasr01 &= ~AST_IO_VGASR1_SD; + + ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x17, 0x7f, vgacr17); + ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, vgasr01); } static void ast_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state) { struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc); struct ast_device *ast = to_ast_device(crtc->dev); - u8 vgacrb6; - - ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, AST_IO_VGASR1_SD); + u8 vgacr17 = 0xff; - vgacrb6 = AST_IO_VGACRB6_VSYNC_OFF | - AST_IO_VGACRB6_HSYNC_OFF; - ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, vgacrb6); + vgacr17 &= ~AST_IO_VGACR17_SYNC_ENABLE; + ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0x17, 0x7f, vgacr17); /* * HW cursors require the underlying primary plane and CRTC to diff --git a/drivers/gpu/drm/ast/ast_reg.h b/drivers/gpu/drm/ast/ast_reg.h index e15adaf3a80e..30578e3b07e4 100644 --- a/drivers/gpu/drm/ast/ast_reg.h +++ b/drivers/gpu/drm/ast/ast_reg.h @@ -29,6 +29,7 @@ #define AST_IO_VGAGRI (0x4E) #define AST_IO_VGACRI (0x54) +#define AST_IO_VGACR17_SYNC_ENABLE BIT(7) /* called "Hardware reset" in docs */ #define AST_IO_VGACR80_PASSWORD (0xa8) #define AST_IO_VGACR99_VGAMEM_RSRV_MASK GENMASK(1, 0) #define AST_IO_VGACRA1_VGAIO_DISABLED BIT(1) -- 2.51.0