diff options
| author | Geert Uytterhoeven | 2019-08-13 11:30:46 +0200 |
|---|---|---|
| committer | Neil Armstrong | 2019-08-14 16:44:04 +0200 |
| commit | 5ad773f9a92f6a0b8d7433921e89b9beb567e5d0 (patch) | |
| tree | 50c4f35e3f07f7ff3d2061a242ab92b7e0f8dbf3 /drivers | |
| parent | fc1ca6e01d0a71fd4bd7a5a7cb8309a9dd48ddbc (diff) | |
drm/bridge: dumb-vga-dac: Fix dereferencing -ENODEV DDC channel
If the VGA connector has no DDC channel, an error pointer will be
dereferenced, e.g. on Salvator-XS:
Unable to handle kernel NULL pointer dereference at virtual address 000000000000017d
...
Call trace:
sysfs_do_create_link_sd.isra.0+0x40/0x108
sysfs_create_link+0x20/0x40
drm_sysfs_connector_add+0xa8/0xc8
drm_connector_register.part.3+0x54/0xb0
drm_connector_register_all+0xb0/0xd0
drm_modeset_register_all+0x54/0x88
drm_dev_register+0x18c/0x1d8
rcar_du_probe+0xe4/0x150
...
This happens because vga->ddc either contains a valid DDC channel
pointer, or -ENODEV, and drm_connector_init_with_ddc() expects a valid
DDC channel pointer, or NULL.
Fix this by resetting vga->ddc to NULL in case of -ENODEV, and replacing
the existing error checks by non-NULL checks.
This is similar to what the HDMI connector driver does.
Fixes: a4f9087e85de141e ("drm/bridge: dumb-vga-dac: Provide ddc symlink in connector sysfs directory")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813093046.4976-1-geert+renesas@glider.be
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/bridge/dumb-vga-dac.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c b/drivers/gpu/drm/bridge/dumb-vga-dac.c index 8ef6539ae78a..7aa789c35882 100644 --- a/drivers/gpu/drm/bridge/dumb-vga-dac.c +++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c @@ -42,7 +42,7 @@ static int dumb_vga_get_modes(struct drm_connector *connector) struct edid *edid; int ret; - if (IS_ERR(vga->ddc)) + if (!vga->ddc) goto fallback; edid = drm_get_edid(connector, vga->ddc); @@ -84,7 +84,7 @@ dumb_vga_connector_detect(struct drm_connector *connector, bool force) * wire the DDC pins, or the I2C bus might not be working at * all. */ - if (!IS_ERR(vga->ddc) && drm_probe_ddc(vga->ddc)) + if (vga->ddc && drm_probe_ddc(vga->ddc)) return connector_status_connected; return connector_status_unknown; @@ -197,6 +197,7 @@ static int dumb_vga_probe(struct platform_device *pdev) if (PTR_ERR(vga->ddc) == -ENODEV) { dev_dbg(&pdev->dev, "No i2c bus specified. Disabling EDID readout\n"); + vga->ddc = NULL; } else { dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n"); return PTR_ERR(vga->ddc); @@ -218,7 +219,7 @@ static int dumb_vga_remove(struct platform_device *pdev) drm_bridge_remove(&vga->bridge); - if (!IS_ERR(vga->ddc)) + if (vga->ddc) i2c_put_adapter(vga->ddc); return 0; |