Re: [PATCH v2 17/28] drm/i2c: tda998x: set the repeat PLL value inrange 0..3

From: Russell King - ARM Linux
Date: Sat Jan 11 2014 - 13:26:15 EST


On Thu, Jan 09, 2014 at 12:05:13PM +0100, Jean-Francois Moine wrote:
>
> Signed-off-by: Jean-Francois Moine <moinejf@xxxxxxx>
> ---
> drivers/gpu/drm/i2c/tda998x_drv.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
> index f60aef9..8a7d8a2 100644
> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
> @@ -220,7 +220,7 @@ struct tda998x_priv {
> # define PLL_SERIAL_1_SRL_IZ(x) (((x) & 3) << 1)
> # define PLL_SERIAL_1_SRL_MAN_IZ (1 << 6)
> #define REG_PLL_SERIAL_2 REG(0x02, 0x01) /* read/write */
> -# define PLL_SERIAL_2_SRL_NOSC(x) (((x) & 3) << 0)
> +# define PLL_SERIAL_2_SRL_NOSC(x) ((x) << 0)
> # define PLL_SERIAL_2_SRL_PR(x) (((x) & 0xf) << 4)
> #define REG_PLL_SERIAL_3 REG(0x02, 0x02) /* read/write */
> # define PLL_SERIAL_3_SRL_CCIR (1 << 0)
> @@ -972,6 +972,11 @@ tda998x_encoder_mode_set(struct drm_encoder *encoder,
> }
>
> div = 148500 / mode->clock;
> + if (div != 0) {
> + div--;
> + if (div > 3)
> + div = 3;
> + }

As the driver currently stands, we know that the clock divider works for
the lower resolution modes. So, as things stand, for 74.25MHz modes,
we get a divisor of one.

Your patch changes this, the divider becomes zero. I wonder whether
you've tested 720p modes at all with this?

--
FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation
in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/