From 171b357d18eea64988ae774aa25b32bbfeb16880 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Thu, 27 Jun 2024 17:27:51 +0200
Subject: [PATCH] drm/ast: Only set VGA SCREEN_DISABLE bit in CRTC code
The SCREEN_DISABLE bit controls scanout from display memory. The bit
affects all planes, so set it only in the CRTC's atomic enable and
disable functions.
A number of bugs affect this fix. First of all, ast_set_std_regs()
tries to set VGASR1 except for the SD bit. But the read bitmask is
invert, so it preserves anything except the SD bit. Fix this by
re-inverting the read mask.
The second issue is that primary-plane and CRTC helpers modify the
SD bit. The bit controls scanout for all planes, primary and HW
cursor, so set it only in the CRTC code.
Further add a constant to represent the SD bit in VGASR1. Keep the
plane's atomic_disable around to make the DRM framework happy.
v2:
- fix typos in commit message
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240627153638.8765-7-tzimmermann@suse.de
---
drivers/gpu/drm/ast/ast_mode.c | 14 +++++++-------
drivers/gpu/drm/ast/ast_reg.h | 1 +
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index e90179bc08427..77358b587098c 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -303,7 +303,7 @@ static void ast_set_std_reg(struct ast_device *ast,
/* Set SEQ; except Screen Disable field */
ast_set_index_reg(ast, AST_IO_VGASRI, 0x00, 0x03);
- ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, stdtable->seq[0]);
+ ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0x20, stdtable->seq[0]);
for (i = 1; i < 4; i++) {
jreg = stdtable->seq[i];
ast_set_index_reg(ast, AST_IO_VGASRI, (i + 1), jreg);
@@ -690,15 +690,15 @@ static void ast_primary_plane_helper_atomic_enable(struct drm_plane *plane,
* Therefore only reprogram the address after enabling the plane.
*/
ast_set_start_address_crt1(ast, (u32)ast_plane->offset);
- ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x1, 0xdf, 0x00);
}
static void ast_primary_plane_helper_atomic_disable(struct drm_plane *plane,
struct drm_atomic_state *state)
{
- struct ast_device *ast = to_ast_device(plane->dev);
-
- ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x1, 0xdf, 0x20);
+ /*
+ * Keep this empty function to avoid calling
+ * atomic_update when disabling the plane.
+ */
}
static int ast_primary_plane_helper_get_scanout_buffer(struct drm_plane *plane,
@@ -1029,14 +1029,14 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
*/
switch (mode) {
case DRM_MODE_DPMS_ON:
- ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0);
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, 0);
+ ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0);
break;
case DRM_MODE_DPMS_STANDBY:
case DRM_MODE_DPMS_SUSPEND:
case DRM_MODE_DPMS_OFF:
ch = mode;
- ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, 0x20);
+ ast_set_index_reg_mask(ast, AST_IO_VGASRI, 0x01, 0xdf, AST_IO_VGASR1_SD);
ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xb6, 0xfc, ch);
break;
}
diff --git a/drivers/gpu/drm/ast/ast_reg.h b/drivers/gpu/drm/ast/ast_reg.h
index 62dddbf3fe569..6326cbdadc82f 100644
--- a/drivers/gpu/drm/ast/ast_reg.h
+++ b/drivers/gpu/drm/ast/ast_reg.h
@@ -22,6 +22,7 @@
#define AST_IO_VGAER_VGA_ENABLE BIT(0)
#define AST_IO_VGASRI (0x44)
+#define AST_IO_VGASR1_SD BIT(5)
#define AST_IO_VGADRR (0x47)
#define AST_IO_VGADWR (0x48)
#define AST_IO_VGAPDR (0x49)
--
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