6.14-stable review patch. If anyone has any objections, please let me know.
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From: Jocelyn Falempe jfalempe@redhat.com
commit c28f72c6ca98e039c2aa5aac6752c416bc31dbab upstream.
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 jfalempe@redhat.com Fixes: 2281475168d2 ("drm/ast: astdp: Perform link training during atomic_enable") Reported-by: Jerry Hoemann jerry.hoemann@hpe.com Tested-by: Jose Lopez jose.lopez@hpe.com Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Dave Airlie airlied@redhat.com Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.12+ Reviewed-by: Thomas Zimmermann tzimmermann@suse.de Link: https://patchwork.freedesktop.org/patch/msgid/20250124141142.2434138-1-jfale... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/ast/ast_dp.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- 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(struc { 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; }