Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1559700

Re: [PATCH v2 11/11] drm/rockchip/dsi: fix insufficient bandwidth of some panel

Show all headers | View raw

On Mon, 16 Jan 2017 18:08:31 +0800, Chris Zhong wrote:

> Set the lanes bps to 1 / 0.9 times of pclk, the margin is not enough
> for some panel, it will cause the screen display is not normal, so
> increases the badnwidth to 1 / 0.8.
> 
> Signed-off-by: Chris Zhong <zyw@rock-chips.com>
> 
> ---
> 
>  drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index 9dfa73d..5a973fe 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -501,8 +501,8 @@ static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi)
>  
>  	mpclk = DIV_ROUND_UP(dsi->mode->clock, MSEC_PER_SEC);
>  	if (mpclk) {
> -		/* take 1 / 0.9, since mbps must big than bandwidth of RGB */
> -		tmp = mpclk * (bpp / dsi->lanes) * 10 / 9;
> +		/* take 1 / 0.8, since mbps must big than bandwidth of RGB */
> +		tmp = mpclk * (bpp / dsi->lanes) * 10 / 8;

This and patch 9 are just hacking around the underlying problem in order
to make particular panels work.  I'm pretty sure the actual issue is the
use of hardcoded values when configuring the PHY, since the PHY
parameters are specified in clock cycles but the MIPI spec requires
absolute time durations.

I posted a series addressing this a while ago, although I screwed up
sending it so some patches were included twice and since no one
expressed any interest I didn't post a cleaned up version.

The relevant patch is here:

https://patchwork.kernel.org/patch/9340193/

>  		if (tmp < max_mbps)
>  			target_mbps = tmp;
>  		else

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2 0/11] Rockchip dw-mipi-dsi driver Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 05/11] drm/rockchip/dsi: add dw-mipi power domain support Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 02/11] drm/rockchip/dsi: dw-mipi: support RK3399 mipi dsi Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 08/11] drm/rockchip/dsi: fix the issue can not send commands Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 04/11] dt-bindings: add power domain node for dw-mipi-rockchip Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 01/11] dt-bindings: add rk3399 support for dw-mipi-rockchip Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
    Re: [PATCH v2 01/11] dt-bindings: add rk3399 support for  dw-mipi-rockchip Rob Herring <robh@kernel.org> - 2017-01-19 16:50 +0100
  [PATCH v2 06/11] drm/rockchip/dsi: return probe defer if attach panel failed Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:10 +0100
  [PATCH v2 10/11] drm/rockchip/dsi: fix phy clk lane stop state timeout Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:20 +0100
  [PATCH v2 03/11] drm/rockchip/dsi: remove mode_valid function Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:20 +0100
  [PATCH v2 11/11] drm/rockchip/dsi: fix insufficient bandwidth of some panel Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:20 +0100
    Re: [PATCH v2 11/11] drm/rockchip/dsi: fix insufficient bandwidth  of some panel John Keeping <john@metanate.com> - 2017-01-16 14:10 +0100
      Re: [PATCH v2 11/11] drm/rockchip/dsi: fix insufficient bandwidth of  some panel Chris Zhong <zyw@rock-chips.com> - 2017-01-17 10:40 +0100
        Re: [PATCH v2 11/11] drm/rockchip/dsi: fix insufficient bandwidth  of some panel John Keeping <john@metanate.com> - 2017-01-17 12:00 +0100
  [PATCH v2 07/11] drm/rockchip/dsi: fix mipi display can't found at init time Chris Zhong <zyw@rock-chips.com> - 2017-01-16 11:20 +0100

csiph-web