Hi Sergei, On Thu, Jul 12, 2012 at 18:53:26, Sergei Shtylyov wrote: > Hello. > > On 11-07-2012 19:14, Manjunathappa, Prakash wrote: > > > Patch works around the below silicon errata: > > During LCDC initialization, there is the potential for a FIFO > > underflow condition to occur. A FIFO underflow condition > > occurs when the input FIFO is completely empty and the LCDC > > raster controller logic that drives data to the output pins > > attempts to fetch data from the FIFO. When a FIFO underflow > > condition occurs, incorrect data will be driven out on the > > LCDC data pins. > > > Software should poll the FUF bit field in the LCD_STAT register > > to check if an error condition has occurred or service the > > interrupt if FUF_EN is enabled when FUF occurs. If the FUF bit > > field has been set to 1, this will indicate an underflow > > condition has occurred and then the software should execute a > > reset of the LCDC via the LPSC. > > > This problem may occur if the LCDC FIFO threshold size > > (LCDDMA_CTRL[TH_FIFO_READY]) is left at its default value after > > reset. Increasing the FIFO threshold size will reduce or > > eliminate underflows. Setting the threshold size to 256 double > > words or larger is recommended. > > > Above issue is described in section 2.1.3 of silicon errata > > http://www.ti.com/lit/er/sprz313e/sprz313e.pdf > > > Signed-off-by: Rajashekhara, Sudhakar <sudhakar.raj@xxxxxx> > > Signed-off-by: Manjunathappa, Prakash <prakash.pm@xxxxxx> > > --- > > drivers/video/da8xx-fb.c | 15 +++++++++++---- > > include/video/da8xx-fb.h | 3 +++ > > 2 files changed, 14 insertions(+), 4 deletions(-) > > > diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c > > index 47118c7..2010dd7 100644 > > --- a/drivers/video/da8xx-fb.c > > +++ b/drivers/video/da8xx-fb.c > > @@ -344,8 +344,8 @@ static void lcd_blit(int load_mode, struct da8xx_fb_par *par) > > lcd_enable_raster(); > > } > > > > -/* Configure the Burst Size of DMA */ > > -static int lcd_cfg_dma(int burst_size) > > +/* Configure the Burst Size and fifo threhold of DMA */ > > +static int lcd_cfg_dma(int burst_size, int fifo_th) > > One space too much. > Yes, I will correct this. Don't know how checkpatch missing it. > > { > > u32 reg; > > > > @@ -719,8 +722,10 @@ static irqreturn_t lcdc_irq_handler_rev02(int irq, void *arg) > > > > if ((stat & LCD_SYNC_LOST) && (stat & LCD_FIFO_UNDERFLOW)) { > > lcd_disable_raster(); > > + clk_disable(par->lcdc_clk); > > lcdc_write(stat, LCD_MASKED_STAT_REG); > > Will LCDC register wrtite work without LCDC clock? > Yes it cannot happen. I will remove it. Thanks, Prakash -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
