Re: [PATCH -next] drm: Fix PM reference leak

[Samuel Zou]

Hi Daniel,

Thanks for your review, I will split the patch and resend.

On 2021/5/21 23:32, Daniel Vetter wrote:

On Fri, May 21, 2021 at 09:03:06PM +0800, Zou Wei wrote:

pm_runtime_get_sync will increment pm usage counter even it failed.
Forgetting to putting operation will result in reference leak here.
Fix it by replacing it with pm_runtime_resume_and_get to keep usage
counter balanced.

Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Zou Wei <zou_...@huawei.com>

Looks good, but can you pls split this up into a patch per driver (vc and
bridge/cdns-dsi here)?

Thanks, Daniel

---
  drivers/gpu/drm/bridge/cdns-dsi.c | 2 +-
  drivers/gpu/drm/vc4/vc4_hdmi.c    | 2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c 
b/drivers/gpu/drm/bridge/cdns-dsi.c
index 76373e3..b31281f 100644
--- a/drivers/gpu/drm/bridge/cdns-dsi.c
+++ b/drivers/gpu/drm/bridge/cdns-dsi.c
@@ -1028,7 +1028,7 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host 
*host,
        struct mipi_dsi_packet packet;
        int ret, i, tx_len, rx_len;

- ret = pm_runtime_get_sync(host->dev);

+       ret = pm_runtime_resume_and_get(host->dev);
        if (ret < 0)
                return ret;

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c

index c27b287..f20a65b 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -798,7 +798,7 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct 
drm_encoder *encoder,
        unsigned long pixel_rate, hsm_rate;
        int ret;

- ret = pm_runtime_get_sync(&vc4_hdmi->pdev->dev);

+       ret = pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev);
        if (ret < 0) {
                DRM_ERROR("Failed to retain power domain: %d\n", ret);
                return;
--
2.6.2