From: Arnd Bergmann arnd@arndb.de
When CONFIG_OF is disabled, building with 'make W=1' produces warnings about out of bounds array access:
drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop': drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below array bounds of 'struct clk *[4]' [-Werror=array-bounds]
Add an error check before the index is used, which helps with the warning, as well as any possible other error condition that may be triggered at runtime.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- drivers/gpu/drm/imx/imx-ldb.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c index dbfe39e2f7f6..1210360cec8a 100644 --- a/drivers/gpu/drm/imx/imx-ldb.c +++ b/drivers/gpu/drm/imx/imx-ldb.c @@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder *encoder) int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN; int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
+ if (mux < 0) { + dev_warn(ldb->dev, + "%s: invalid mux\n", __func__); + return; + } + drm_panel_prepare(imx_ldb_ch->panel);
if (dual) { @@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder, int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder); u32 bus_format = imx_ldb_ch->bus_format;
+ if (mux < 0) { + dev_warn(ldb->dev, + "%s: invalid mux\n", __func__); + return; + } + if (mode->clock > 170000) { dev_warn(ldb->dev, "%s: mode exceeds 170 MHz pixel clock\n", __func__);
Hi Arnd,
On Tue, Mar 23, 2021 at 10:05 AM Arnd Bergmann arnd@kernel.org wrote:
What about making the driver depend on OF instead (like it is done in DRM_IMX_HDMI) ?
--- a/drivers/gpu/drm/imx/Kconfig +++ b/drivers/gpu/drm/imx/Kconfig @@ -27,7 +27,7 @@ config DRM_IMX_TVE
config DRM_IMX_LDB tristate "Support for LVDS displays" - depends on DRM_IMX && MFD_SYSCON + depends on DRM_IMX && MFD_SYSCON && OF depends on COMMON_CLK select DRM_PANEL help
Hi Fabio,
On Tue, 2021-03-23 at 11:02 -0300, Fabio Estevam wrote:
The below patch made DRM_IMX_HDMI depend on OF, because of_drm_find_bridge() is not defined when OF is disabled.
drm/imx: dw_hdmi-imx: depend on OF to fix randconfig compile tests on x86_64
It doesn't look like DRM_IMX_LDB is in the same case.
Moreover, even if OF is enabled, drm_of_encoder_active_endpoint() is likely to return -EINVAL. So, it looks ok to add an error check.
Regards, Liu Ying
On Tue, 2021-03-23 at 14:05 +0100, Arnd Bergmann wrote:
[]
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
[]
trivia:
Any real reason to make this 2 lines? It fits nicely in 80 chars. Maybe:
dev_warn(ldb->dev, "%s: invalid mux: %d\n", __func__, mux);
or maybe:
dev_warn(ldb->dev, "%s: invalid mux: %pe\n", __func__, ERR_PTR(mux));
@@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder,
[]
etc...
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