On Fri, May 29, 2020 at 03:33:17PM +0300, Andy Shevchenko wrote:
> acpi_dev_get_resources() does perform the NULL pointer check against
> ACPI companion device which is given as function parameter. Thus,
> there is no need to duplicate this check in the caller.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Sorry, I did look at this but apparently forgot to reply...
> ---
> drivers/gpu/drm/i915/display/intel_dsi_vbt.c | 24 ++++++++------------
> 1 file changed, 10 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> index 574dcfec9577..6f9e08cda964 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> @@ -426,23 +426,19 @@ static void i2c_acpi_find_adapter(struct intel_dsi *intel_dsi,
> {
> struct drm_device *drm_dev = intel_dsi->base.base.dev;
> struct device *dev = &drm_dev->pdev->dev;
> - struct acpi_device *acpi_dev;
> + struct acpi_device *acpi_dev = ACPI_COMPANION(dev);
> struct list_head resource_list;
> struct i2c_adapter_lookup lookup;
>
> - acpi_dev = ACPI_COMPANION(dev);
> - if (acpi_dev) {
> - memset(&lookup, 0, sizeof(lookup));
> - lookup.slave_addr = slave_addr;
> - lookup.intel_dsi = intel_dsi;
> - lookup.dev_handle = acpi_device_handle(acpi_dev);
> -
> - INIT_LIST_HEAD(&resource_list);
> - acpi_dev_get_resources(acpi_dev, &resource_list,
> - i2c_adapter_lookup,
> - &lookup);
> - acpi_dev_free_resource_list(&resource_list);
> - }
> + memset(&lookup, 0, sizeof(lookup));
> + lookup.slave_addr = slave_addr;
> + lookup.intel_dsi = intel_dsi;
> + lookup.dev_handle = acpi_device_handle(acpi_dev);
struct i2c_adapter_lookup lookup = {
.slave_addr = ...
};
?
> +
> + INIT_LIST_HEAD(&resource_list);
Declare as LIST_HEAD(resource_list); ?
> + acpi_dev_get_resources(acpi_dev, &resource_list,
> + i2c_adapter_lookup, &lookup);
> + acpi_dev_free_resource_list(&resource_list);
I was very confused by this code since on the first glance it appears to
absolutely nothing. After a deeper look it looks like
i2c_adapter_lookup() magically mutates intel_dsi->i2c_bus_num.
Did I mention I hate functions with side effects? IMO would be much
better if i2c_adapter_lookup() did what it says on the tin and just
returned the adapter number and let the caller deal with it. But
this is a pre-existing issue with the code and so not directly related
to your patch.
> }
> #else
> static inline void i2c_acpi_find_adapter(struct intel_dsi *intel_dsi,
> --
> 2.26.2
>
> _______________________________________________
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> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Ville Syrjälä
Intel
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