On Wed, Aug 07, 2019 at 08:49:52AM +0000, David Laight wrote:
From: Sasha Levin
Sent: 06 August 2019 22:33
From: Colin Ian King colin.king@canonical.com
[ Upstream commit 1bbbab097a05276e312dd2462791d32b21ceb1ee ]
Currently the retry counter is not being decremented, leading to a potential infinite spin if the scalar_reads don't change state.
Addresses-Coverity: ("Infinite loop") Fixes: 280e54c9f614 ("drm/exynos: scaler: Reset hardware before starting the operation") Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Inki Dae inki.dae@samsung.com Signed-off-by: Sasha Levin sashal@kernel.org
drivers/gpu/drm/exynos/exynos_drm_scaler.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_scaler.c b/drivers/gpu/drm/exynos/exynos_drm_scaler.c index ec9c1b7d31033..8989f8af716b7 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_scaler.c +++ b/drivers/gpu/drm/exynos/exynos_drm_scaler.c @@ -94,12 +94,12 @@ static inline int scaler_reset(struct scaler_context *scaler) scaler_write(SCALER_CFG_SOFT_RESET, SCALER_CFG); do { cpu_relax();
- } while (retry > 1 &&
- } while (--retry > 1 && scaler_read(SCALER_CFG) & SCALER_CFG_SOFT_RESET); do { cpu_relax(); scaler_write(1, SCALER_INT_EN);
- } while (retry > 0 && scaler_read(SCALER_INT_EN) != 1);
} while (--retry > 0 && scaler_read(SCALER_INT_EN) != 1);
return retry ? 0 : -EIO;
If the first loop hits the retry limit the second loop won't be right and the final return value will be 0.
This looks like an upstream problem as well, no?
-- Thanks, Sasha