1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
index 7264aa3b20ff..6b7f2da6f907 100644
--- a/drivers/video/da8xx-fb.c
+++ b/drivers/video/da8xx-fb.c
@@ -30,6 +30,7 @@
 #include <linux/clk.h>
 #include <linux/cpufreq.h>
 #include <linux/console.h>
+#include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/lcm.h>
 #include <video/da8xx-fb.h>
@@ -161,6 +162,13 @@ struct da8xx_fb_par {
         wait_queue_head_t       vsync_wait;
         int                     vsync_flag;
         int                     vsync_timeout;
+        spinlock_t              lock_for_chan_update;
+
+        /*
+         * LCDC has 2 ping pong DMA channels, channel 0
+         * and channel 1.
+         */
+        unsigned int            which_dma_channel_done;
 #ifdef CONFIG_CPU_FREQ
         struct notifier_block   freq_transition;
         unsigned int            lcd_fck_rate;
@@ -741,6 +749,7 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq, void *arg)
                 lcdc_write(stat, LCD_MASKED_STAT_REG);
 
                 if (stat & LCD_END_OF_FRAME0) {
+                        par->which_dma_channel_done = 0;
                         lcdc_write(par->dma_start,
                                    LCD_DMA_FRM_BUF_BASE_ADDR_0_REG);
                         lcdc_write(par->dma_end,
@@ -750,6 +759,7 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq, void *arg)
                 }
 
                 if (stat & LCD_END_OF_FRAME1) {
+                        par->which_dma_channel_done = 1;
                         lcdc_write(par->dma_start,
                                    LCD_DMA_FRM_BUF_BASE_ADDR_1_REG);
                         lcdc_write(par->dma_end,
@@ -796,6 +806,7 @@ static irqreturn_t lcdc_irq_handler_rev01(int irq, void *arg)
                 lcdc_write(stat, LCD_STAT_REG);
 
                 if (stat & LCD_END_OF_FRAME0) {
+                        par->which_dma_channel_done = 0;
                         lcdc_write(par->dma_start,
                                    LCD_DMA_FRM_BUF_BASE_ADDR_0_REG);
                         lcdc_write(par->dma_end,
@@ -805,6 +816,7 @@ static irqreturn_t lcdc_irq_handler_rev01(int irq, void *arg)
                 }
 
                 if (stat & LCD_END_OF_FRAME1) {
+                        par->which_dma_channel_done = 1;
                         lcdc_write(par->dma_start,
                                    LCD_DMA_FRM_BUF_BASE_ADDR_1_REG);
                         lcdc_write(par->dma_end,
@@ -1053,6 +1065,7 @@ static int da8xx_pan_display(struct fb_var_screeninfo *var,
         struct fb_fix_screeninfo    *fix = &fbi->fix;
         unsigned int end;
         unsigned int start;
+        unsigned long irq_flags;
 
         if (var->xoffset != fbi->var.xoffset ||
                         var->yoffset != fbi->var.yoffset) {
@@ -1070,6 +1083,21 @@ static int da8xx_pan_display(struct fb_var_screeninfo *var,
                         end     = start + fbi->var.yres * fix->line_length - 1;
                         par->dma_start  = start;
                         par->dma_end    = end;
+                        spin_lock_irqsave(&par->lock_for_chan_update,
+                                        irq_flags);
+                        if (par->which_dma_channel_done == 0) {
+                                lcdc_write(par->dma_start,
+                                           LCD_DMA_FRM_BUF_BASE_ADDR_0_REG);
+                                lcdc_write(par->dma_end,
+                                           LCD_DMA_FRM_BUF_CEILING_ADDR_0_REG);
+                        } else if (par->which_dma_channel_done == 1) {
+                                lcdc_write(par->dma_start,
+                                           LCD_DMA_FRM_BUF_BASE_ADDR_1_REG);
+                                lcdc_write(par->dma_end,
+                                           LCD_DMA_FRM_BUF_CEILING_ADDR_1_REG);
+                        }
+                        spin_unlock_irqrestore(&par->lock_for_chan_update,
+                                        irq_flags);
                 }
         }
 
@@ -1299,6 +1327,8 @@ static int __devinit fb_probe(struct platform_device *device)
         /* initialize the vsync wait queue */
         init_waitqueue_head(&par->vsync_wait);
         par->vsync_timeout = HZ / 5;
+        par->which_dma_channel_done = -1;
+        spin_lock_init(&par->lock_for_chan_update);
 
         /* Register the Frame Buffer  */
         if (register_framebuffer(da8xx_fb_info) < 0) {