From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Eric Anholt <eric@anholt.net>, David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH v2] drm/pl111: Use 64-bit arithmetic instead of 32-bit
Date: Wed, 4 Jul 2018 09:22:55 -0500 [thread overview]
Message-ID: <20180704142255.GA8614@embeddedor.com> (raw)
Add suffix ULL to constant 1000 in order to give the compiler complete
information about the proper arithmetic to use.
Notice that such constant is used in a context that expects an
expression of type u64 (64 bits, unsigned) and the following
expression is currently being evaluated using 32-bit arithmetic:
mode->clock * 1000
Addresses-Coverity-ID: 1466139 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Changes in v2:
- Use suffix ULL instead of UL.
drivers/gpu/drm/pl111/pl111_display.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c
index a432eb7..754f6b2 100644
--- a/drivers/gpu/drm/pl111/pl111_display.c
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -63,7 +63,7 @@ pl111_mode_valid(struct drm_crtc *crtc,
* We use the pixelclock to also account for interlaced modes, the
* resulting bandwidth is in bytes per second.
*/
- bw = mode->clock * 1000; /* In Hz */
+ bw = mode->clock * 1000ULL; /* In Hz */
bw = bw * mode->hdisplay * mode->vdisplay * cpp;
bw = div_u64(bw, mode->htotal * mode->vtotal);
--
2.7.4
next reply other threads:[~2018-07-04 14:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-04 14:22 Gustavo A. R. Silva [this message]
2018-07-17 18:40 ` [PATCH v2] drm/pl111: Use 64-bit arithmetic instead of 32-bit Eric Anholt
2018-07-17 18:40 ` Eric Anholt
2018-07-17 19:52 ` Gustavo A. R. Silva
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