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drm/arm/hdlcd: Actually validate CRTC modes

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[ Upstream commit b96151edced4edb6a18aa89a5fa02c7066efff45 ]

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: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Robin Murphy 2019-05-17 17:37:21 +01:00 committed by Greg Kroah-Hartman
parent 1fcb0e3895
commit 7c7c88deb1
1 changed files with 5 additions and 6 deletions
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11
drivers/gpu/drm/arm/hdlcd_crtc.c
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@ -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,