Hi,
On Fri, 2008-11-07 at 12:55 -0800, ext Rick Bronson wrote:
> 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?
I think the correct solution would be to find out why we get sync lost
errors and fix that. Your patch just hides the problem.
However, I agree that it's not good to just keep spamming the error,
possibly making the board freeze. The new DSS turns the display off
after 100 error messages. But I don't think just hiding the interrupt is
a good change.
>
> Thanks,
>
> Rick
Tomi
>
> --- 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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