Folks,
Please take a look at this change to drivers/video/omap/dispc.c. It
addresses a problem seen on some boots of OMAP's. On about 1 in 30
boots one gets an endless stream of interrupts from the
DISPC_IRQ_SYNC_LOST bit in the DISPC_IRQSTATUS register. The
following messages are printed.
omapfb omapfb: irq error status 4020
The correct solution to this problem is to perform a "soft reset"
but that requires a bit of re-architecturing of the code as the init
routine would have to be split up, etc. See the OMAP pdf, search for
"To clear a synchronization lost interrupt".
This patch allows the above error message to get printed once and
then disables further DISPC_IRQ_SYNC_LOST interrups.
Comments?
Thanks,
Rick
--- linux-omap-2.6/drivers/video/omap/dispc.c.~1~ 2008-11-04 14:23:38.000000000 -0800
+++ linux-omap-2.6/drivers/video/omap/dispc.c 2008-11-07 12:34:54.000000000 -0800
@@ -157,7 +157,7 @@ struct resmap {
#define MAX_IRQ_HANDLERS 4
-static struct {
+static struct omapfb_dispc {
void __iomem *base;
struct omapfb_mem_desc mem_desc;
@@ -169,6 +169,7 @@ static struct {
int ext_mode;
+ u32 irq_error_mask; /* mask used for errors */
struct {
u32 irq_mask;
void (*callback)(void *);
@@ -812,16 +813,16 @@ static void set_lcd_timings(void)
panel->pixel_clock = fck / lck_div / pck_div / 1000;
}
-static void recalc_irq_mask(void)
+static void recalc_irq_mask(struct omapfb_dispc *p_dispc)
{
int i;
- unsigned long irq_mask = DISPC_IRQ_MASK_ERROR;
+ unsigned long irq_mask = p_dispc->irq_error_mask;
for (i = 0; i < MAX_IRQ_HANDLERS; i++) {
- if (!dispc.irq_handlers[i].callback)
+ if (!p_dispc->irq_handlers[i].callback)
continue;
- irq_mask |= dispc.irq_handlers[i].irq_mask;
+ irq_mask |= p_dispc->irq_handlers[i].irq_mask;
}
enable_lcd_clocks(1);
@@ -843,7 +844,7 @@ int omap_dispc_request_irq(unsigned long
dispc.irq_handlers[i].irq_mask = irq_mask;
dispc.irq_handlers[i].callback = callback;
dispc.irq_handlers[i].data = data;
- recalc_irq_mask();
+ recalc_irq_mask(&dispc);
return 0;
}
@@ -863,7 +864,7 @@ void omap_dispc_free_irq(unsigned long i
dispc.irq_handlers[i].irq_mask = 0;
dispc.irq_handlers[i].callback = NULL;
dispc.irq_handlers[i].data = NULL;
- recalc_irq_mask();
+ recalc_irq_mask(&dispc);
return;
}
}
@@ -884,6 +885,10 @@ static irqreturn_t omap_dispc_irq_handle
complete(&dispc.frame_done);
if (stat & DISPC_IRQ_MASK_ERROR) {
+ if (stat & DISPC_IRQ_SYNC_LOST) { /* only allow sync lost once or we end up... */
+ dispc.irq_error_mask &= ~DISPC_IRQ_SYNC_LOST; /* with a barrage of interrupts */
+ recalc_irq_mask(&dispc);
+ }
if (printk_ratelimit()) {
dev_err(dispc.fbdev->dev, "irq error status %04x\n",
stat & 0x7fff);
@@ -897,6 +902,7 @@ static irqreturn_t omap_dispc_irq_handle
}
dispc_write_reg(DISPC_IRQSTATUS, stat);
+ stat = dispc_read_reg(DISPC_IRQSTATUS);
enable_lcd_clocks(0);
@@ -1432,7 +1438,8 @@ static int omap_dispc_init(struct omapfb
l = dispc_read_reg(DISPC_IRQSTATUS);
dispc_write_reg(DISPC_IRQSTATUS, l);
- recalc_irq_mask();
+ dispc.irq_error_mask = DISPC_IRQ_MASK_ERROR; /* init error mask */
+ recalc_irq_mask(&dispc);
if ((r = request_irq(INT_24XX_DSS_IRQ, omap_dispc_irq_handler,
0, MODULE_NAME, fbdev)) < 0) {
--
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