From be280fddfd645ea0ce4c7a26692c3d1115447e32 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@linaro.org>
Date: Mon, 12 Aug 2024 11:29:38 +0300
Subject: [PATCH] drm/ast: astdp: fix loop timeout check
This code has an issue because it loops until "i" is set to UINT_MAX but
the test for failure assumes that "i" is set to zero. The result is that
it will only print an error message if we succeed on the very last try.
Reformat the loop to count forwards instead of backwards.
Fixes: 2281475168d2 ("drm/ast: astdp: Perform link training during atomic_enable")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/1ba8da25-2d09-4924-a4ff-c0714bfbb192@stanley.mountain
---
drivers/gpu/drm/ast/ast_dp.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_dp.c b/drivers/gpu/drm/ast/ast_dp.c
index 5d07678b502c2..ca022c287785e 100644
--- a/drivers/gpu/drm/ast/ast_dp.c
+++ b/drivers/gpu/drm/ast/ast_dp.c
@@ -146,18 +146,19 @@ void ast_dp_power_on_off(struct drm_device *dev, bool on)
void ast_dp_link_training(struct ast_device *ast)
{
struct drm_device *dev = &ast->base;
- unsigned int i = 10;
+ int i;
- while (i--) {
- u8 vgacrdc = ast_get_index_reg(ast, AST_IO_VGACRI, 0xdc);
+ for (i = 0; i < 10; i++) {
+ u8 vgacrdc;
- if (vgacrdc & AST_IO_VGACRDC_LINK_SUCCESS)
- break;
if (i)
msleep(100);
+
+ vgacrdc = ast_get_index_reg(ast, AST_IO_VGACRI, 0xdc);
+ if (vgacrdc & AST_IO_VGACRDC_LINK_SUCCESS)
+ return;
}
- if (!i)
- drm_err(dev, "Link training failed\n");
+ drm_err(dev, "Link training failed\n");
}
void ast_dp_set_on_off(struct drm_device *dev, bool on)
--
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