[v2] drm/loongson: use managed KMS polling

[PATCH v2] drm/loongson: use managed KMS polling

Posted by Myeonghun Pak 1 week, 6 days ago

lsdc_pci_probe() initializes KMS polling before setting up vblank support,
requesting the IRQ and registering the DRM device. If any of those later
steps fails, probe returns without finalizing polling. The driver also
never finalizes polling on regular removal.

Use drmm_kms_helper_poll_init() so polling is tied to the DRM device
lifetime and automatically finalized on probe failure and device removal.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
Cc: stable@vger.kernel.org
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
Changes in v2:
- Switch to drmm_kms_helper_poll_init() as suggested by Icenowy Zheng
  and Thomas Zimmermann instead of adding manual cleanup paths.

 drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
index abf5bf68ee..4b97750897 100644
--- a/drivers/gpu/drm/loongson/lsdc_drv.c
+++ b/drivers/gpu/drm/loongson/lsdc_drv.c
@@ -292,7 +292,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	vga_client_register(pdev, lsdc_vga_set_decode);
 
-	drm_kms_helper_poll_init(ddev);
+	drmm_kms_helper_poll_init(ddev);
 
 	if (loongson_vblank) {
 		ret = drm_vblank_init(ddev, descp->num_of_crtc);
-- 
2.47.1

Re: [PATCH v2] drm/loongson: use managed KMS polling

Posted by Huacai Chen 1 week, 6 days ago

On Tue, May 12, 2026 at 2:37 PM Myeonghun Pak <mhun512@gmail.com> wrote:
>
> lsdc_pci_probe() initializes KMS polling before setting up vblank support,
> requesting the IRQ and registering the DRM device. If any of those later
> steps fails, probe returns without finalizing polling. The driver also
> never finalizes polling on regular removal.
>
> Use drmm_kms_helper_poll_init() so polling is tied to the DRM device
> lifetime and automatically finalized on probe failure and device removal.
>
> This issue was identified during our ongoing static-analysis research while
> reviewing kernel code.
In the subject line please s/use/Use/g, others LGTM.
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>

>
> Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
> Cc: stable@vger.kernel.org
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> ---
> Changes in v2:
> - Switch to drmm_kms_helper_poll_init() as suggested by Icenowy Zheng
>   and Thomas Zimmermann instead of adding manual cleanup paths.
>
>  drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
> index abf5bf68ee..4b97750897 100644
> --- a/drivers/gpu/drm/loongson/lsdc_drv.c
> +++ b/drivers/gpu/drm/loongson/lsdc_drv.c
> @@ -292,7 +292,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>
>         vga_client_register(pdev, lsdc_vga_set_decode);
>
> -       drm_kms_helper_poll_init(ddev);
> +       drmm_kms_helper_poll_init(ddev);
>
>         if (loongson_vblank) {
>                 ret = drm_vblank_init(ddev, descp->num_of_crtc);
> --
> 2.47.1
>

Re: [PATCH v2] drm/loongson: use managed KMS polling

Posted by Myeonghun Pak 1 week, 5 days ago

Hi Huacai,

Thanks, I sent a v3 with the subject fixed and added the Reviewed-by and
Acked-by tags.

Best regards,
Myeonghun

2026년 5월 12일 (화) 오후 5:11, Huacai Chen <chenhuacai@kernel.org>님이 작성:
>
> On Tue, May 12, 2026 at 2:37 PM Myeonghun Pak <mhun512@gmail.com> wrote:
> >
> > lsdc_pci_probe() initializes KMS polling before setting up vblank support,
> > requesting the IRQ and registering the DRM device. If any of those later
> > steps fails, probe returns without finalizing polling. The driver also
> > never finalizes polling on regular removal.
> >
> > Use drmm_kms_helper_poll_init() so polling is tied to the DRM device
> > lifetime and automatically finalized on probe failure and device removal.
> >
> > This issue was identified during our ongoing static-analysis research while
> > reviewing kernel code.
> In the subject line please s/use/Use/g, others LGTM.
> Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
>
> >
> > Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
> > Cc: stable@vger.kernel.org
> > Co-developed-by: Ijae Kim <ae878000@gmail.com>
> > Signed-off-by: Ijae Kim <ae878000@gmail.com>
> > Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> > ---
> > Changes in v2:
> > - Switch to drmm_kms_helper_poll_init() as suggested by Icenowy Zheng
> >   and Thomas Zimmermann instead of adding manual cleanup paths.
> >
> >  drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
> > index abf5bf68ee..4b97750897 100644
> > --- a/drivers/gpu/drm/loongson/lsdc_drv.c
> > +++ b/drivers/gpu/drm/loongson/lsdc_drv.c
> > @@ -292,7 +292,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> >
> >         vga_client_register(pdev, lsdc_vga_set_decode);
> >
> > -       drm_kms_helper_poll_init(ddev);
> > +       drmm_kms_helper_poll_init(ddev);
> >
> >         if (loongson_vblank) {
> >                 ret = drm_vblank_init(ddev, descp->num_of_crtc);
> > --
> > 2.47.1
> >

Re: [PATCH v2] drm/loongson: use managed KMS polling

Posted by Jianmin Lv 1 week, 6 days ago


On 2026/5/12 下午2:36, Myeonghun Pak wrote:
> lsdc_pci_probe() initializes KMS polling before setting up vblank support,
> requesting the IRQ and registering the DRM device. If any of those later
> steps fails, probe returns without finalizing polling. The driver also
> never finalizes polling on regular removal.
> 
> Use drmm_kms_helper_poll_init() so polling is tied to the DRM device
> lifetime and automatically finalized on probe failure and device removal.
> 
> This issue was identified during our ongoing static-analysis research while
> reviewing kernel code.
> 
> Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
> Cc: stable@vger.kernel.org
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

Acked-by: Jianmin Lv <lvjianmin@loongson.cn>

> ---
> Changes in v2:
> - Switch to drmm_kms_helper_poll_init() as suggested by Icenowy Zheng
>    and Thomas Zimmermann instead of adding manual cleanup paths.
> 
>   drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
> index abf5bf68ee..4b97750897 100644
> --- a/drivers/gpu/drm/loongson/lsdc_drv.c
> +++ b/drivers/gpu/drm/loongson/lsdc_drv.c
> @@ -292,7 +292,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   
>   	vga_client_register(pdev, lsdc_vga_set_decode);
>   
> -	drm_kms_helper_poll_init(ddev);
> +	drmm_kms_helper_poll_init(ddev);
>   
>   	if (loongson_vblank) {
>   		ret = drm_vblank_init(ddev, descp->num_of_crtc);
>

Re: [PATCH v2] drm/loongson: use managed KMS polling

Posted by Thomas Zimmermann 1 week, 6 days ago


Am 12.05.26 um 08:36 schrieb Myeonghun Pak:
> lsdc_pci_probe() initializes KMS polling before setting up vblank support,
> requesting the IRQ and registering the DRM device. If any of those later
> steps fails, probe returns without finalizing polling. The driver also
> never finalizes polling on regular removal.
>
> Use drmm_kms_helper_poll_init() so polling is tied to the DRM device
> lifetime and automatically finalized on probe failure and device removal.
>
> This issue was identified during our ongoing static-analysis research while
> reviewing kernel code.
>
> Fixes: f39db26c5428 ("drm: Add kms driver for loongson display controller")
> Cc: stable@vger.kernel.org
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
> Changes in v2:
> - Switch to drmm_kms_helper_poll_init() as suggested by Icenowy Zheng
>    and Thomas Zimmermann instead of adding manual cleanup paths.
>
>   drivers/gpu/drm/loongson/lsdc_drv.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
> index abf5bf68ee..4b97750897 100644
> --- a/drivers/gpu/drm/loongson/lsdc_drv.c
> +++ b/drivers/gpu/drm/loongson/lsdc_drv.c
> @@ -292,7 +292,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   
>   	vga_client_register(pdev, lsdc_vga_set_decode);
>   
> -	drm_kms_helper_poll_init(ddev);
> +	drmm_kms_helper_poll_init(ddev);
>   
>   	if (loongson_vblank) {
>   		ret = drm_vblank_init(ddev, descp->num_of_crtc);

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)