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Message-ID: <46dc6803-47f0-4434-9794-08307604e450@linux.dev>
Date: Mon, 7 Apr 2025 23:29:55 +0530
From: Aradhya Bhatia <aradhya.bhatia@...ux.dev>
To: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
Jyri Sarha <jyri.sarha@....fi>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-phy@...ts.infradead.org, Francesco Dolcini <francesco@...cini.it>,
Devarsh Thakkar <devarsht@...com>
Subject: Re: [PATCH v2 12/18] drm/bridge: cdns-dsi: Drop checks that shouldn't
be in .mode_valid()
Hi Tomi,
On 02/04/25 19:00, Tomi Valkeinen wrote:
> The docs say about mode_valid():
>
> "it is not allowed to look at anything else but the passed-in mode, and
> validate it against configuration-invariant hardware constraints"
>
> We're doing a lot more than just looking at the mode. The main issue
> here is that we're doing checks based on the pixel clock, before we know
> what the pixel clock from the crtc actually is.
>
> So, drop the checks from .mode_valid(). This also allows us to remove
> the 'mode_valid_check' parameter from internal functions, and the
> related code.
>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
> ---
> drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 44 ++++++++------------------
> 1 file changed, 14 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> index e85c8652c96e..cf783680b1b4 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> @@ -469,25 +469,17 @@ static unsigned int dpi_to_dsi_timing(unsigned int dpi_timing,
>
> static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
> const struct drm_display_mode *mode,
> - struct cdns_dsi_cfg *dsi_cfg,
> - bool mode_valid_check)
> + struct cdns_dsi_cfg *dsi_cfg)
> {
> struct cdns_dsi_output *output = &dsi->output;
> u32 dpi_hsa, dpi_hbp, dpi_hfp, dpi_hact;
> bool sync_pulse;
> int bpp;
>
> - if (mode_valid_check) {
> - dpi_hsa = mode->hsync_end - mode->hsync_start;
> - dpi_hbp = mode->htotal - mode->hsync_end;
> - dpi_hfp = mode->hsync_start - mode->hdisplay;
> - dpi_hact = mode->hdisplay;
> - } else {
> - dpi_hsa = mode->crtc_hsync_end - mode->crtc_hsync_start;
> - dpi_hbp = mode->crtc_htotal - mode->crtc_hsync_end;
> - dpi_hfp = mode->crtc_hsync_start - mode->crtc_hdisplay;
> - dpi_hact = mode->crtc_hdisplay;
> - }
> + dpi_hsa = mode->crtc_hsync_end - mode->crtc_hsync_start;
> + dpi_hbp = mode->crtc_htotal - mode->crtc_hsync_end;
> + dpi_hfp = mode->crtc_hsync_start - mode->crtc_hdisplay;
> + dpi_hact = mode->crtc_hdisplay;
>
> memset(dsi_cfg, 0, sizeof(*dsi_cfg));
>
> @@ -518,8 +510,7 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
> static int cdns_dsi_adjust_phy_config(struct cdns_dsi *dsi,
> struct cdns_dsi_cfg *dsi_cfg,
> struct phy_configure_opts_mipi_dphy *phy_cfg,
> - const struct drm_display_mode *mode,
> - bool mode_valid_check)
> + const struct drm_display_mode *mode)
> {
> struct cdns_dsi_output *output = &dsi->output;
> unsigned long long dlane_bps;
> @@ -549,11 +540,11 @@ static int cdns_dsi_adjust_phy_config(struct cdns_dsi *dsi,
> if (dsi_htotal % lanes)
> adj_dsi_htotal += lanes - (dsi_htotal % lanes);
>
> - dpi_hz = (mode_valid_check ? mode->clock : mode->crtc_clock) * 1000;
> + dpi_hz = mode->crtc_clock * 1000;
> dlane_bps = (unsigned long long)dpi_hz * adj_dsi_htotal;
>
> /* data rate in bytes/sec is not an integer, refuse the mode. */
> - dpi_htotal = mode_valid_check ? mode->htotal : mode->crtc_htotal;
> + dpi_htotal = mode->crtc_htotal;
> if (do_div(dlane_bps, lanes * dpi_htotal))
> return -EINVAL;
>
> @@ -569,27 +560,25 @@ static int cdns_dsi_adjust_phy_config(struct cdns_dsi *dsi,
>
> static int cdns_dsi_check_conf(struct cdns_dsi *dsi,
> const struct drm_display_mode *mode,
> - struct cdns_dsi_cfg *dsi_cfg,
> - bool mode_valid_check)
> + struct cdns_dsi_cfg *dsi_cfg)
> {
> struct cdns_dsi_output *output = &dsi->output;
> struct phy_configure_opts_mipi_dphy *phy_cfg = &output->phy_opts.mipi_dphy;
> unsigned int nlanes = output->dev->lanes;
> - int mode_clock = (mode_valid_check ? mode->clock : mode->crtc_clock);
> unsigned long req_hs_clk_rate;
> int ret;
>
> - ret = cdns_dsi_mode2cfg(dsi, mode, dsi_cfg, mode_valid_check);
> + ret = cdns_dsi_mode2cfg(dsi, mode, dsi_cfg);
> if (ret)
> return ret;
>
> - ret = phy_mipi_dphy_get_default_config(mode_clock * 1000,
> + ret = phy_mipi_dphy_get_default_config(mode->crtc_clock * 1000,
> mipi_dsi_pixel_format_to_bpp(output->dev->format),
> nlanes, phy_cfg);
> if (ret)
> return ret;
>
> - ret = cdns_dsi_adjust_phy_config(dsi, dsi_cfg, phy_cfg, mode, mode_valid_check);
> + ret = cdns_dsi_adjust_phy_config(dsi, dsi_cfg, phy_cfg, mode);
> if (ret)
> return ret;
>
> @@ -635,8 +624,7 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> struct cdns_dsi_input *input = bridge_to_cdns_dsi_input(bridge);
> struct cdns_dsi *dsi = input_to_dsi(input);
> struct cdns_dsi_output *output = &dsi->output;
> - struct cdns_dsi_cfg dsi_cfg;
> - int bpp, ret;
> + int bpp;
>
> /*
> * VFP_DSI should be less than VFP_DPI and VFP_DSI should be at
> @@ -654,10 +642,6 @@ cdns_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> if ((mode->hdisplay * bpp) % 32)
> return MODE_H_ILLEGAL;
>
> - ret = cdns_dsi_check_conf(dsi, mode, &dsi_cfg, true);
> - if (ret)
> - return MODE_BAD;
> -
> return MODE_OK;
> }
>
> @@ -996,7 +980,7 @@ static int cdns_dsi_bridge_atomic_check(struct drm_bridge *bridge,
> adjusted_crtc_mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
> adjusted_crtc_mode->flags |= DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC;
>
> - return cdns_dsi_check_conf(dsi, mode, dsi_cfg, false);
> + return cdns_dsi_check_conf(dsi, mode, dsi_cfg);
With this patch, the driver shifts to using the crtc_* values during the
check phase, and then, it is brought back to using non crtc_* values in
the next patch.
Should this patch just drop the cdns_dsi_check_conf() check from
.mode_valid() instead, and let the next patch phase out the
mdoe_valid_check parameter as the driver simultaneously shifts to using
the non crtc_* values throughout?
--
Regards
Aradhya
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