On Tue, Sep 11, 2018 at 01:33:25PM +0200, Maxime Ripard wrote:
Having DRM_SUN4I built-in but DRM_SUN8I_MIXER as a loadable module results in a link error, as we try to access a symbol from the sun8i_tcon_top.ko module:
ERROR: "sun8i_tcon_top_de_config" [drivers/gpu/drm/sun4i/sun4i-tcon.ko] undefined! ERROR: "sun8i_tcon_top_set_hdmi_src" [drivers/gpu/drm/sun4i/sun4i-tcon.ko] undefined! ERROR: "sun8i_tcon_top_of_table" [drivers/gpu/drm/sun4i/sun4i-tcon.ko] undefined!
This solves the problem by adding a silent symbol for the tcon_top module, building it as a separate module in exactly the cases that we need it, but in a way that it is reachable by the other modules.
Fixes: cf77d79b4e29 ("drm/sun4i: tcon: Add another way for matching mixers with tcon") Fixes: 0305189afb32 ("drm/sun4i: tcon: Add support for R40 TCON") Tested-by: Jon Hunter jonathanh@nvidia.com Signed-off-by: Maxime Ripard maxime.ripard@bootlin.com
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
But I can't help myself and drop the usual questions when I see a small soc driver with more Kconfigs than anything else ... is all this pain worth it? I know that maybe the desktop approach of stuffing half a million lines of driver code into one .ko might be a bit too much for socs, but this seems overkill.
I'm also pretty sure it's not justified by any real data, compared to overall code size of a drm stack, that shows it's a substantial enough saving that it's worth it.
Imo, if you really care about building a minimal driver, stuff everything into one .ko and then LTO out the uneeded bits. We've done these experiments for i915, that _actually_ saves a ton of binary size, with fairly minimal code and maintenance impact. Still, we decided the payoff is simply too small to bother making it a production thing.
Cheers, Daniel
drivers/gpu/drm/sun4i/sun4i_tcon.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 4834c90b4912..c78cd35a1294 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -974,7 +974,8 @@ static bool sun4i_tcon_connected_to_tcon_top(struct device_node *node)
remote = of_graph_get_remote_node(node, 0, -1); if (remote) {
ret = !!of_match_node(sun8i_tcon_top_of_table, remote);
ret = !!(IS_ENABLED(CONFIG_DRM_SUN8I_TCON_TOP) &&of_match_node(sun8i_tcon_top_of_table, remote));@@ -1402,13 +1403,20 @@ static int sun8i_r40_tcon_tv_set_mux(struct sun4i_tcon *tcon, if (!pdev) return -EINVAL;
- if (encoder->encoder_type == DRM_MODE_ENCODER_TMDS) {
- if (IS_ENABLED(CONFIG_DRM_SUN8I_TCON_TOP) &&
encoder->encoder_type == DRM_MODE_ENCODER_TMDS) {
- return sun8i_tcon_top_de_config(&pdev->dev, tcon->id, id);
- if (IS_ENABLED(CONFIG_DRM_SUN8I_TCON_TOP)) {
ret = sun8i_tcon_top_de_config(&pdev->dev, tcon->id, id);if (ret)return ret;- }
- return 0;
}
static const struct sun4i_tcon_quirks sun4i_a10_quirks = {
2.17.1
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