Commit b96151ed authored by Robin Murphy's avatar Robin Murphy Committed by Liviu Dudau
Browse files

drm/arm/hdlcd: Actually validate CRTC modes 



Rather than allowing any old mode through, then subsequently refusing
unmatchable clock rates in atomic_check when it's too late to back out
and pick a different mode, let's do that validation up-front where it
will cause unsupported modes to be correctly pruned in the first place.

This also eliminates an issue whereby a perceived clock rate of 0 would
cause atomic disable to fail and prevent the module from being unloaded.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarLiviu Dudau <liviu.dudau@arm.com>
parent 6a88e0c1

drivers/gpu/drm/arm/hdlcd_crtc.c

+5 −6
Original line number Diff line number Diff line
@@ -186,20 +186,19 @@ static void hdlcd_crtc_atomic_disable(struct drm_crtc *crtc, 
	clk_disable_unprepare(hdlcd->clk);

}



static int hdlcd_crtc_atomic_check(struct drm_crtc *crtc,

				   struct drm_crtc_state *state)

static enum drm_mode_status hdlcd_crtc_mode_valid(struct drm_crtc *crtc,

		const struct drm_display_mode *mode)

{

	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);

	struct drm_display_mode *mode = &state->adjusted_mode;

	long rate, clk_rate = mode->clock * 1000;



	rate = clk_round_rate(hdlcd->clk, clk_rate);

	if (rate != clk_rate) {

		/* clock required by mode not supported by hardware */

		return -EINVAL;

		return MODE_NOCLOCK;

	}



	return 0;

	return MODE_OK;

}



static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
@@ -220,7 +219,7 @@ static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc, 
}



static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {

	.atomic_check	= hdlcd_crtc_atomic_check,

	.mode_valid	= hdlcd_crtc_mode_valid,

	.atomic_begin	= hdlcd_crtc_atomic_begin,

	.atomic_enable	= hdlcd_crtc_atomic_enable,

	.atomic_disable	= hdlcd_crtc_atomic_disable,

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