linux-kernel - [ 31/73] drm/cirrus: deal with bo reserve fail in dirty update path

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Message-Id: <20130509222801.352617181@linuxfoundation.org>
Date:	Thu,  9 May 2013 15:31:54 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Dave Airlie <airlied@...hat.com>
Subject: [ 31/73] drm/cirrus: deal with bo reserve fail in dirty update path

3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Airlie <airlied@...hat.com>

commit f3b2bbdc8a87a080ccd23d27fca4b87d61340dd4 upstream.

Port over the mgag200 fix to cirrus as it suffers the same issue.

    On F19 testing, it was noticed we get a lot of errors in dmesg
    about being unable to reserve the buffer when plymouth starts,
    this is due to the buffer being in the process of migrating,
    so it makes sense we can't reserve it.

    In order to deal with it, this adds delayed updates for the dirty
    updates, when the bo is unreservable, in the normal console case
    this shouldn't ever happen, its just when plymouth or X is
    pushing the console bo to system memory.

Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/cirrus/cirrus_drv.h   |    2 +
 drivers/gpu/drm/cirrus/cirrus_fbdev.c |   38 +++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/cirrus/cirrus_ttm.c   |    2 -
 3 files changed, 40 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/cirrus/cirrus_drv.h
+++ b/drivers/gpu/drm/cirrus/cirrus_drv.h
@@ -154,6 +154,8 @@ struct cirrus_fbdev {
 	struct list_head fbdev_list;
 	void *sysram;
 	int size;
+	int x1, y1, x2, y2; /* dirty rect */
+	spinlock_t dirty_lock;
 };
 
 struct cirrus_bo {
--- a/drivers/gpu/drm/cirrus/cirrus_fbdev.c
+++ b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
@@ -26,16 +26,51 @@ static void cirrus_dirty_update(struct c
 	int bpp = (afbdev->gfb.base.bits_per_pixel + 7)/8;
 	int ret;
 	bool unmap = false;
+	bool store_for_later = false;
+	int x2, y2;
+	unsigned long flags;
 
 	obj = afbdev->gfb.obj;
 	bo = gem_to_cirrus_bo(obj);
 
+	/*
+	 * try and reserve the BO, if we fail with busy
+	 * then the BO is being moved and we should
+	 * store up the damage until later.
+	 */
 	ret = cirrus_bo_reserve(bo, true);
 	if (ret) {
-		DRM_ERROR("failed to reserve fb bo\n");
+		if (ret != -EBUSY)
+			return;
+		store_for_later = true;
+	}
+
+	x2 = x + width - 1;
+	y2 = y + height - 1;
+	spin_lock_irqsave(&afbdev->dirty_lock, flags);
+
+	if (afbdev->y1 < y)
+		y = afbdev->y1;
+	if (afbdev->y2 > y2)
+		y2 = afbdev->y2;
+	if (afbdev->x1 < x)
+		x = afbdev->x1;
+	if (afbdev->x2 > x2)
+		x2 = afbdev->x2;
+
+	if (store_for_later) {
+		afbdev->x1 = x;
+		afbdev->x2 = x2;
+		afbdev->y1 = y;
+		afbdev->y2 = y2;
+		spin_unlock_irqrestore(&afbdev->dirty_lock, flags);
 		return;
 	}
 
+	afbdev->x1 = afbdev->y1 = INT_MAX;
+	afbdev->x2 = afbdev->y2 = 0;
+	spin_unlock_irqrestore(&afbdev->dirty_lock, flags);
+
 	if (!bo->kmap.virtual) {
 		ret = ttm_bo_kmap(&bo->bo, 0, bo->bo.num_pages, &bo->kmap);
 		if (ret) {
@@ -282,6 +317,7 @@ int cirrus_fbdev_init(struct cirrus_devi
 
 	cdev->mode_info.gfbdev = gfbdev;
 	gfbdev->helper.funcs = &cirrus_fb_helper_funcs;
+	spin_lock_init(&gfbdev->dirty_lock);
 
 	ret = drm_fb_helper_init(cdev->dev, &gfbdev->helper,
 				 cdev->num_crtc, CIRRUSFB_CONN_LIMIT);
--- a/drivers/gpu/drm/cirrus/cirrus_ttm.c
+++ b/drivers/gpu/drm/cirrus/cirrus_ttm.c
@@ -321,7 +321,7 @@ int cirrus_bo_reserve(struct cirrus_bo *
 
 	ret = ttm_bo_reserve(&bo->bo, true, no_wait, false, 0);
 	if (ret) {
-		if (ret != -ERESTARTSYS)
+		if (ret != -ERESTARTSYS && ret != -EBUSY)
 			DRM_ERROR("reserve failed %p\n", bo);
 		return ret;
 	}


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