[PATCH AUTOSEL 4.9 29/34] drm/panel: type promotion bug in s6e8aa0_read_mtp_id()

Sasha Levin
2018-09-15T01:35:13Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit cd0e0ca69109d025b1a1b6609f70682db62138b0 ]

The ARRAY_SIZE() macro is type size_t. If s6e8aa0_dcs_read() returns a
negative error code, then "ret < ARRAY_SIZE(id)" is false because the
negative error code is type promoted to a high positive value.

Fixes: 02051ca06371 ("drm/panel: add S6E8AA0 driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180704093807.s3lqsb2v6dg2k43d@kili.mountain
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c b/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c
index a188a3959f1a..6ad827b93ae1 100644
--- a/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c
@@ -823,7 +823,7 @@ static void s6e8aa0_read_mtp_id(struct s6e8aa0 *ctx)
int ret, i;

ret = s6e8aa0_dcs_read(ctx, 0xd1, id, ARRAY_SIZE(id));
- if (ret < ARRAY_SIZE(id) || id[0] == 0x00) {
+ if (ret < 0 || ret < ARRAY_SIZE(id) || id[0] == 0x00) {
dev_err(ctx->dev, "read id failed\n");
ctx->error = -EIO;
return;
--
2.17.1