diff options
Diffstat (limited to 'drivers/gpu/drm/omapdrm/omap_crtc.c')
| -rw-r--r-- | drivers/gpu/drm/omapdrm/omap_crtc.c | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c index cc85c16cbc2a..1b8154e58d18 100644 --- a/drivers/gpu/drm/omapdrm/omap_crtc.c +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c @@ -1,7 +1,5 @@ /* - * drivers/gpu/drm/omapdrm/omap_crtc.c - * - * Copyright (C) 2011 Texas Instruments + * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ * Author: Rob Clark <rob@ti.com> * * This program is free software; you can redistribute it and/or modify it @@ -23,6 +21,7 @@ #include <drm/drm_crtc_helper.h> #include <drm/drm_mode.h> #include <drm/drm_plane_helper.h> +#include <linux/math64.h> #include "omap_drv.h" @@ -400,6 +399,41 @@ static void omap_crtc_atomic_disable(struct drm_crtc *crtc, drm_crtc_vblank_off(crtc); } +static enum drm_mode_status omap_crtc_mode_valid(struct drm_crtc *crtc, + const struct drm_display_mode *mode) +{ + struct omap_drm_private *priv = crtc->dev->dev_private; + + /* Check for bandwidth limit */ + if (priv->max_bandwidth) { + /* + * Estimation for the bandwidth need of a given mode with one + * full screen plane: + * bandwidth = resolution * 32bpp * (pclk / (vtotal * htotal)) + * ^^ Refresh rate ^^ + * + * The interlaced mode is taken into account by using the + * pixelclock in the calculation. + * + * The equation is rearranged for 64bit arithmetic. + */ + uint64_t bandwidth = mode->clock * 1000; + unsigned int bpp = 4; + + bandwidth = bandwidth * mode->hdisplay * mode->vdisplay * bpp; + bandwidth = div_u64(bandwidth, mode->htotal * mode->vtotal); + + /* + * Reject modes which would need more bandwidth if used with one + * full resolution plane (most common use case). + */ + if (priv->max_bandwidth < bandwidth) + return MODE_BAD; + } + + return MODE_OK; +} + static void omap_crtc_mode_set_nofb(struct drm_crtc *crtc) { struct omap_crtc *omap_crtc = to_omap_crtc(crtc); @@ -621,6 +655,7 @@ static const struct drm_crtc_helper_funcs omap_crtc_helper_funcs = { .atomic_flush = omap_crtc_atomic_flush, .atomic_enable = omap_crtc_atomic_enable, .atomic_disable = omap_crtc_atomic_disable, + .mode_valid = omap_crtc_mode_valid, }; /* ----------------------------------------------------------------------------- |