Hi

Am 24.01.25 um 15:11 schrieb Jocelyn Falempe:
ast_dp_is_connected() used to also check for link training success
to report the DP connector as connected. Without this check, the
physical_status is always connected. So if no monitor is present, it
will fail to read the EDID and set the default resolution to 640x480
instead of 1024x768.

Signed-off-by: Jocelyn Falempe <[email protected]>
Fixes: 2281475168d2 ("drm/ast: astdp: Perform link training during 
atomic_enable")
Cc: Thomas Zimmermann <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # v6.12+

I cannot reproduce the problem, but the patch looks correct. My AST2600 with ASTDP still works correctly with the patch allied.

Reviewed-by: Thomas Zimmermann <[email protected]>

Best regards
Thomas

---
  drivers/gpu/drm/ast/ast_dp.c | 6 ++++++
  1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/ast/ast_dp.c b/drivers/gpu/drm/ast/ast_dp.c
index 0e282b7b167c..30aad5c0112a 100644
--- a/drivers/gpu/drm/ast/ast_dp.c
+++ b/drivers/gpu/drm/ast/ast_dp.c
@@ -17,6 +17,12 @@ static bool ast_astdp_is_connected(struct ast_device *ast)
  {
        if (!ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDF, 
AST_IO_VGACRDF_HPD))
                return false;
+       /*
+        * HPD might be set even if no monitor is connected, so also check that
+        * the link training was successful.
+        */
+       if (!ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xDC, 
AST_IO_VGACRDC_LINK_SUCCESS))
+               return false;
        return true;
  }
base-commit: 798047e63ac970f105c49c22e6d44df901c486b2

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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