[PATCH 11/16] drm/fb-helper: fixup up set_config semantics
Rob Clark
robdclark at gmail.com
Mon Feb 11 15:15:59 PST 2013
On Thu, Jan 24, 2013 at 10:20 AM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> While doing the modeset rework for drm/i915 I've noticed that the fb
> helper is very liberal with the semantics of the ->set_config
> interface:
> - It doesn't bother clearing stale modes (e.g. when unpluggint a
s/unpluggint/unplugging/
> screen).
> - It unconditionally sets and the fb, even if no mode will be set on a
s/and the fb/the fb/ ?
> given crtc.
> - The initial setup is a bit fun since we need to pick crtcs to decide
> the desired fb size, but also should set the modeset->fb pointer.
> Explain what's going on in the fixup code after the fb is allocated.
>
> The crtc helper didn't really care, but the new i915 modeset
> infrastructure did, so I've had to add a bunch of special-cases to
> catch this.
>
> Fix this all up and enforce the interface by converting the checks in
> drm/i915/intel_display.c to BUG_ONs.
>
maybe nitpicking, but how about a matching set of BUG_ONs in crtc
helper, so someone messing with this code with a driver that still
uses crtc helper would catch the same issues?
Anyways, basically seems reasonable.
But thanks for making me look at code that so far I've mostly tried to
avoid looking at :-P
It does seem like the initial-config code could somehow be simpler than it is..
Anyways, while looking at that, it occurs to me that we should remove
mode, and saved_fb from 'struct drm_fb_helper'
BR,
-R
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> drivers/gpu/drm/drm_fb_helper.c | 27 +++++++++++++++++++++++----
> drivers/gpu/drm/i915/intel_display.c | 11 +++--------
> 2 files changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index dbf0020..5c73a12 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -689,7 +689,6 @@ int drm_fb_helper_set_par(struct fb_info *info)
> struct drm_fb_helper *fb_helper = info->par;
> struct drm_device *dev = fb_helper->dev;
> struct fb_var_screeninfo *var = &info->var;
> - struct drm_crtc *crtc;
> int ret;
> int i;
>
> @@ -700,7 +699,6 @@ int drm_fb_helper_set_par(struct fb_info *info)
>
> drm_modeset_lock_all(dev);
> for (i = 0; i < fb_helper->crtc_count; i++) {
> - crtc = fb_helper->crtc_info[i].mode_set.crtc;
> ret = drm_mode_set_config_internal(&fb_helper->crtc_info[i].mode_set);
> if (ret) {
> drm_modeset_unlock_all(dev);
> @@ -841,9 +839,17 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
>
> info = fb_helper->fbdev;
>
> - /* set the fb pointer */
> + /*
> + * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
> + * events, but at init time drm_setup_crtcs needs to be called before
> + * the fb is allocated (since we need to figure out the desired size of
> + * the fb before we can allocate it ...). Hence we need to fix things up
> + * here again.
> + */
> for (i = 0; i < fb_helper->crtc_count; i++)
> - fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
> + if (fb_helper->crtc_info[i].mode_set.num_connectors)
> + fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
> +
>
> if (new_fb) {
> info->var.pixclock = 0;
> @@ -1314,6 +1320,7 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
> for (i = 0; i < fb_helper->crtc_count; i++) {
> modeset = &fb_helper->crtc_info[i].mode_set;
> modeset->num_connectors = 0;
> + modeset->fb = NULL;
> }
>
> for (i = 0; i < fb_helper->connector_count; i++) {
> @@ -1330,9 +1337,21 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
> modeset->mode = drm_mode_duplicate(dev,
> fb_crtc->desired_mode);
> modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
> + modeset->fb = fb_helper->fb;
> }
> }
>
> + /* Clear out any old modes if there are no more connected outputs. */
> + for (i = 0; i < fb_helper->crtc_count; i++) {
> + modeset = &fb_helper->crtc_info[i].mode_set;
> + if (modeset->num_connectors == 0) {
> + BUG_ON(modeset->fb);
> + BUG_ON(modeset->num_connectors);
> + if (modeset->mode)
> + drm_mode_destroy(dev, modeset->mode);
> + modeset->mode = NULL;
> + }
> + }
> out:
> kfree(crtcs);
> kfree(modes);
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 055b24a..7e3dd0f 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7940,14 +7940,9 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
> BUG_ON(!set->crtc);
> BUG_ON(!set->crtc->helper_private);
>
> - if (!set->mode)
> - set->fb = NULL;
> -
> - /* The fb helper likes to play gross jokes with ->mode_set_config.
> - * Unfortunately the crtc helper doesn't do much at all for this case,
> - * so we have to cope with this madness until the fb helper is fixed up. */
> - if (set->fb && set->num_connectors == 0)
> - return 0;
> + /* Enforce sane interface api - has been abused by the fb helper. */
> + BUG_ON(!set->mode && set->fb);
> + BUG_ON(set->fb && set->num_connectors == 0);
>
> if (set->fb) {
> DRM_DEBUG_KMS("[CRTC:%d] [FB:%d] #connectors=%d (x y) (%i %i)\n",
> --
> 1.7.10.4
>
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