lkml.org 
[lkml]   [2019]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH AUTOSEL 5.2 51/59] drm/exynos: fix missing decrement of retry counter
    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

    \
     
     \ /
      Last update: 2019-08-18 03:49    [W:5.090 / U:0.260 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site