drm/ast: Warn about unsupported TX chips

A number of TX chips are listed in VGACRD1, but not supported by
the ast driver. Whether any existing product uses such a chip is
unknown. Warn if the driver encounters any. We can then add
support as necessary.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Suggested-by: Jocelyn Falempe <jfalempe@redhat.com>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240916082920.56234-4-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 7289bdc6066ef037fb580ea1ac4744196b17db5e..bc37c65305d48604dc4be857a37ff29b55fbf44f 100644 (file)
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -76,7 +76,22 @@ static void ast_detect_tx_chip(struct ast_device *ast, bool need_post)
        };
 
        struct drm_device *dev = &ast->base;
-       u8 jreg;
+       u8 jreg, vgacrd1;
+
+       /*
+        * Several of the listed TX chips are not explicitly supported
+        * by the ast driver. If these exist in real-world devices, they
+        * are most likely reported as VGA or SIL164 outputs. We warn here
+        * to get bug reports for these devices. If none come in for some
+        * time, we can begin to fail device probing on these values.
+        */
+       vgacrd1 = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xd1, AST_IO_VGACRD1_TX_TYPE_MASK);
+       drm_WARN(dev, vgacrd1 == AST_IO_VGACRD1_TX_ITE66121_VBIOS,
+                "ITE IT66121 detected, 0x%x, Gen%lu\n", vgacrd1, AST_GEN(ast));
+       drm_WARN(dev, vgacrd1 == AST_IO_VGACRD1_TX_CH7003_VBIOS,
+                "Chrontel CH7003 detected, 0x%x, Gen%lu\n", vgacrd1, AST_GEN(ast));
+       drm_WARN(dev, vgacrd1 == AST_IO_VGACRD1_TX_ANX9807_VBIOS,
+                "Analogix ANX9807 detected, 0x%x, Gen%lu\n", vgacrd1, AST_GEN(ast));
 
        /* Check 3rd Tx option (digital output afaik) */
        ast->tx_chip = AST_TX_NONE;