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Message-ID: <20181004103422.GL9144@intel.com>
Date: Thu, 4 Oct 2018 13:34:22 +0300
From: Ville Syrjälä <ville.syrjala@...ux.intel.com>
To: Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>
Cc: dri-devel@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>,
Alexey Brodkin <alexey.brodkin@...opsys.com>,
linux-kernel@...r.kernel.org, stable@...r.kernel.org,
linux-snps-arc@...ts.infradead.org, Sean Paul <sean@...rly.run>
Subject: Re: [PATCH v2] drm: fb-helper: Reject all pixel format changing
requests
On Wed, Oct 03, 2018 at 07:45:38PM +0300, Eugeniy Paltsev wrote:
> drm fbdev emulation doesn't support changing the pixel format at all,
> so reject all pixel format changing requests.
>
> Cc: stable@...r.kernel.org
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>
> ---
> Changes v1->v2:
> * Reject all pixel format changing request, not just the invalid ones.
>
> drivers/gpu/drm/drm_fb_helper.c | 91 ++++++++++++-----------------------------
> 1 file changed, 26 insertions(+), 65 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 16ec93b75dbf..48598d7f673f 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1580,6 +1580,25 @@ int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
> }
> EXPORT_SYMBOL(drm_fb_helper_ioctl);
>
> +static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
> + const struct fb_var_screeninfo *var_2)
> +{
> + return var_1->bits_per_pixel == var_2->bits_per_pixel &&
> + var_1->grayscale == var_2->grayscale &&
> + var_1->red.offset == var_2->red.offset &&
> + var_1->red.length == var_2->red.length &&
> + var_1->red.msb_right == var_2->red.msb_right &&
> + var_1->green.offset == var_2->green.offset &&
> + var_1->green.length == var_2->green.length &&
> + var_1->green.msb_right == var_2->green.msb_right &&
> + var_1->blue.offset == var_2->blue.offset &&
> + var_1->blue.length == var_2->blue.length &&
> + var_1->blue.msb_right == var_2->blue.msb_right &&
> + var_1->transp.offset == var_2->transp.offset &&
> + var_1->transp.length == var_2->transp.length &&
> + var_1->transp.msb_right == var_2->transp.msb_right;
> +}
Could have shortened a bit with memcmp() but this works too.
Reviewed-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
I suppose we really should be doing the same for most of the rest of
var_screeninfo as we don't allow changing the timings/etc. either.
> +
> /**
> * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
> * @var: screeninfo to check
> @@ -1590,7 +1609,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
> {
> struct drm_fb_helper *fb_helper = info->par;
> struct drm_framebuffer *fb = fb_helper->fb;
> - int depth;
>
> if (var->pixclock != 0 || in_dbg_master())
> return -EINVAL;
> @@ -1610,72 +1628,15 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
> return -EINVAL;
> }
>
> - switch (var->bits_per_pixel) {
> - case 16:
> - depth = (var->green.length == 6) ? 16 : 15;
> - break;
> - case 32:
> - depth = (var->transp.length > 0) ? 32 : 24;
> - break;
> - default:
> - depth = var->bits_per_pixel;
> - break;
> - }
> -
> - switch (depth) {
> - case 8:
> - var->red.offset = 0;
> - var->green.offset = 0;
> - var->blue.offset = 0;
> - var->red.length = 8;
> - var->green.length = 8;
> - var->blue.length = 8;
> - var->transp.length = 0;
> - var->transp.offset = 0;
> - break;
> - case 15:
> - var->red.offset = 10;
> - var->green.offset = 5;
> - var->blue.offset = 0;
> - var->red.length = 5;
> - var->green.length = 5;
> - var->blue.length = 5;
> - var->transp.length = 1;
> - var->transp.offset = 15;
> - break;
> - case 16:
> - var->red.offset = 11;
> - var->green.offset = 5;
> - var->blue.offset = 0;
> - var->red.length = 5;
> - var->green.length = 6;
> - var->blue.length = 5;
> - var->transp.length = 0;
> - var->transp.offset = 0;
> - break;
> - case 24:
> - var->red.offset = 16;
> - var->green.offset = 8;
> - var->blue.offset = 0;
> - var->red.length = 8;
> - var->green.length = 8;
> - var->blue.length = 8;
> - var->transp.length = 0;
> - var->transp.offset = 0;
> - break;
> - case 32:
> - var->red.offset = 16;
> - var->green.offset = 8;
> - var->blue.offset = 0;
> - var->red.length = 8;
> - var->green.length = 8;
> - var->blue.length = 8;
> - var->transp.length = 8;
> - var->transp.offset = 24;
> - break;
> - default:
> + /*
> + * drm fbdev emulation doesn't support changing the pixel format at all,
> + * so reject all pixel format changing requests.
> + */
> + if (!drm_fb_pixel_format_equal(var, &info->var)) {
> + DRM_DEBUG("fbdev emulation doesn't support changing the pixel format\n");
> return -EINVAL;
> }
> +
> return 0;
> }
> EXPORT_SYMBOL(drm_fb_helper_check_var);
> --
> 2.14.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel
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