linux-kernel - [PATCH v3] drm/fb-helper: add virtual screen size check to drm_fb_helper_check

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Date:   Fri, 12 Aug 2022 14:30:07 +0300
From:   Andrey Strachuk <strochuk@...ras.ru>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
Cc:     Andrey Strachuk <strochuk@...ras.ru>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Helge Deller <deller@....de>, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, ldv-project@...uxtesting.org
Subject: [PATCH v3] drm/fb-helper: add virtual screen size check to drm_fb_helper_check_var()

Make sure that virtual screen size is not less than physical screen one.

Reviewed-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Andrey Strachuk <strochuk@...ras.ru>
---
 drivers/gpu/drm/drm_fb_helper.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 2d4cee6a10ff..ea07c97bc5a9 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1355,6 +1355,12 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 	    (drm_format_info_block_height(fb->format, 0) > 1))
 		return -EINVAL;
 
+	/* make sure that virtual resolution >= physical resolution */
+	if (var->xres_virtual < var->xres)
+		var->xres_virtual = var->xres;
+	if (var->yres_virtual < var->yres)
+		var->yres_virtual = var->yres;
+
 	/*
 	 * Changes struct fb_var_screeninfo are currently not pushed back
 	 * to KMS, hence fail if different settings are requested.
-- 
2.25.1