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Commit 2ec8e378 authored by Tomi Valkeinen's avatar Tomi Valkeinen
Browse files

drm/omap: fix output enable/disable sequence 



At the moment it's quite easy to get the following errors when the HDMI
output is enabled or disabled:

[drm:omap_crtc_error_irq] *ERROR* tv: errors: 00008000

The reason for the errors is that the omapdrm driver doesn't properly
handle the sync-lost irqs that happen when enabling the DIGIT crtc,
which is used for HDMI and analog TV. The driver does disable the
sync-lost irq properly, but it fails to wait until the output has been
fully enabled (i.e. the first vsync), so the sync-lost errors are still
seen occasionally.

This patch makes the omapdrm act the same way as the omapfb does:

- When enabling a display, we'll wait for the first vsync.
- When disabling a display, we'll wait for framedone if available, or
  odd and even vsyncs.

These changes make sure the output is fully enabled or disabled at the
end of the function.

Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: default avatarSanjay Singh Rawat <sanjay.rawat@linaro.org>
Reviewed-by: default avatarRob Clark <robdclark@gmail.com>
parent c9eaa447

drivers/gpu/drm/omapdrm/omap_crtc.c

+27 −19
Original line number Diff line number Diff line
@@ -528,39 +528,47 @@ static void set_enabled(struct drm_crtc *crtc, bool enable) 
	struct drm_device *dev = crtc->dev;

	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);

	enum omap_channel channel = omap_crtc->channel;

	struct omap_irq_wait *wait = NULL;

	struct omap_irq_wait *wait;

	u32 framedone_irq, vsync_irq;

	int ret;



	if (dispc_mgr_is_enabled(channel) == enable)

		return;



	/* ignore sync-lost irqs during enable/disable */

	/*

	 * Digit output produces some sync lost interrupts during the first

	 * frame when enabling, so we need to ignore those.

	 */

	omap_irq_unregister(crtc->dev, &omap_crtc->error_irq);



	if (dispc_mgr_get_framedone_irq(channel)) {

		if (!enable) {

			wait = omap_irq_wait_init(dev,

					dispc_mgr_get_framedone_irq(channel), 1);

		}

	framedone_irq = dispc_mgr_get_framedone_irq(channel);

	vsync_irq = dispc_mgr_get_vsync_irq(channel);



	if (enable) {

		wait = omap_irq_wait_init(dev, vsync_irq, 1);

	} else {

		/*

		 * When we disable digit output, we need to wait until fields

		 * are done.  Otherwise the DSS is still working, and turning

		 * off the clocks prevents DSS from going to OFF mode. And when

		 * enabling, we need to wait for the extra sync losts

		 * When we disable the digit output, we need to wait for

		 * FRAMEDONE to know that DISPC has finished with the output.

		 *

		 * OMAP2/3 does not have FRAMEDONE irq for digit output, and in

		 * that case we need to use vsync interrupt, and wait for both

		 * even and odd frames.

		 */

		wait = omap_irq_wait_init(dev,

				dispc_mgr_get_vsync_irq(channel), 2);



		if (framedone_irq)

			wait = omap_irq_wait_init(dev, framedone_irq, 1);

		else

			wait = omap_irq_wait_init(dev, vsync_irq, 2);

	}



	dispc_mgr_enable(channel, enable);



	if (wait) {

		int ret = omap_irq_wait(dev, wait, msecs_to_jiffies(100));

	ret = omap_irq_wait(dev, wait, msecs_to_jiffies(100));

	if (ret) {

		dev_err(dev->dev, "%s: timeout waiting for %s\n",

				omap_crtc->name, enable ? "enable" : "disable");

	}

	}



	omap_irq_register(crtc->dev, &omap_crtc->error_irq);

}