On Wed, Oct 02, 2013 at 10:07:39AM +0100, Chris Wilson wrote:
> If the firmware is not builtin and userspace is not yet running, we can
> stall the boot process for a minute whilst the firmware loader times
> out. This is contrary to expectations of providing a builtin EDID!
> 
> In the process, we can rearrange the code to make the error handling
> more resilient and prevent gcc warning about unitialised variables along
> the error paths.
> 
> v2: Load builtins first, fix gcc second (Jani) and cosmetics (Ville).
> 
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
> Cc: Jani Nikula <jani.nik...@linux.intel.com>
> ---
>  drivers/gpu/drm/drm_edid_load.c |  117 
> +++++++++++++++++++++------------------
>  1 file changed, 63 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
> index 271b42b..9aed4d9 100644
> --- a/drivers/gpu/drm/drm_edid_load.c
> +++ b/drivers/gpu/drm/drm_edid_load.c
> @@ -32,7 +32,7 @@ MODULE_PARM_DESC(edid_firmware, "Do not probe monitor, use 
> specified EDID blob "
>       "from built-in data or /lib/firmware instead. ");
>  
>  #define GENERIC_EDIDS 5
> -static char *generic_edid_name[GENERIC_EDIDS] = {
> +static const char *generic_edid_name[GENERIC_EDIDS] = {
>       "edid/1024x768.bin",
>       "edid/1280x1024.bin",
>       "edid/1600x1200.bin",
> @@ -40,7 +40,7 @@ static char *generic_edid_name[GENERIC_EDIDS] = {
>       "edid/1920x1080.bin",
>  };
>  
> -static u8 generic_edid[GENERIC_EDIDS][128] = {
> +static const u8 generic_edid[GENERIC_EDIDS][128] = {
>       {
>       0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
>       0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> @@ -133,63 +133,77 @@ static u8 generic_edid[GENERIC_EDIDS][128] = {
>       },
>  };
>  
> +static int edid_size(const u8 *edid)
> +{
> +     return (edid[0x7e] + 1) * EDID_LENGTH;
> +}
> +
> +static bool edid_check_size(const u8 *data, int data_size)
> +{
> +     if (data[0x7e] > 0x7e)
> +             return false;

That should be 'if (data_size <= 0x7e) return false;' no?

Or maybe just 'data_size < EDID_LENGTH' since we anyway want a
multiple of EDID_LENGTH.


> +
> +     if (edid_size(data) != data_size)
> +             return false;
> +
> +     return true;
> +}
> +
>  static u8 *edid_load(struct drm_connector *connector, const char *name,
>                       const char *connector_name)
>  {
> -     const struct firmware *fw;
> -     struct platform_device *pdev;
> -     u8 *fwdata = NULL, *edid, *new_edid;
> -     int fwsize, expected;
> -     int builtin = 0, err = 0;
> +     const struct firmware *fw = NULL;
> +     const u8 *fwdata;
> +     u8 *edid;
> +     int fwsize, builtin;
>       int i, valid_extensions = 0;
>       bool print_bad_edid = !connector->bad_edid_counter || (drm_debug & 
> DRM_UT_KMS);
>  
> -     pdev = platform_device_register_simple(connector_name, -1, NULL, 0);
> -     if (IS_ERR(pdev)) {
> -             DRM_ERROR("Failed to register EDID firmware platform device "
> -                 "for connector \"%s\"\n", connector_name);
> -             err = -EINVAL;
> -             goto out;
> -     }
> -
> -     err = request_firmware(&fw, name, &pdev->dev);
> -     platform_device_unregister(pdev);
> -
> -     if (err) {
> -             i = 0;
> -             while (i < GENERIC_EDIDS && strcmp(name, generic_edid_name[i]))
> -                     i++;
> -             if (i < GENERIC_EDIDS) {
> -                     err = 0;
> -                     builtin = 1;
> +     builtin = 0;
> +     for (i = 0; i < GENERIC_EDIDS; i++) {
> +             if (strcmp(name, generic_edid_name[i]) == 0) {
>                       fwdata = generic_edid[i];
>                       fwsize = sizeof(generic_edid[i]);
> +                     builtin = 1;
> +                     break;
>               }
>       }
> +     if (!builtin) {
> +             struct platform_device *pdev;
> +             int err;
>  
> -     if (err) {
> -             DRM_ERROR("Requesting EDID firmware \"%s\" failed (err=%d)\n",
> -                 name, err);
> -             goto out;
> -     }
> +             pdev = platform_device_register_simple(connector_name, -1, 
> NULL, 0);
> +             if (IS_ERR(pdev)) {
> +                     DRM_ERROR("Failed to register EDID firmware platform 
> device "
> +                               "for connector \"%s\"\n", connector_name);
> +                     return ERR_CAST(pdev);
> +             }
>  
> -     if (fwdata == NULL) {
> -             fwdata = (u8 *) fw->data;
> +             err = request_firmware(&fw, name, &pdev->dev);
> +             platform_device_unregister(pdev);
> +             if (err) {
> +                     DRM_ERROR("Requesting EDID firmware \"%s\" failed 
> (err=%d)\n",
> +                               name, err);
> +                     return ERR_PTR(err);
> +             }
> +
> +             fwdata = (const u8 *)fw->data;

No need to cast now that fwdata is const.

>               fwsize = fw->size;
>       }
>  
> -     expected = (fwdata[0x7e] + 1) * EDID_LENGTH;
> -     if (expected != fwsize) {
> +     if (!edid_check_size(fwdata, fwsize)) {
>               DRM_ERROR("Size of EDID firmware \"%s\" is invalid "
> -                 "(expected %d, got %d)\n", name, expected, (int) fwsize);
> -             err = -EINVAL;
> -             goto relfw_out;
> +                       "(expected %d, got %d, limit %d)\n", name,
> +                       edid_size(fwdata), (int)fwsize,
> +                       0x7f*EDID_LENGTH);
> +             edid = ERR_PTR(-EINVAL);
> +             goto out;
>       }
>  
>       edid = kmemdup(fwdata, fwsize, GFP_KERNEL);
>       if (edid == NULL) {
> -             err = -ENOMEM;
> -             goto relfw_out;
> +             edid = ERR_PTR(-ENOMEM);
> +             goto out;
>       }
>  
>       if (!drm_edid_block_valid(edid, 0, print_bad_edid)) {
> @@ -197,8 +211,8 @@ static u8 *edid_load(struct drm_connector *connector, 
> const char *name,
>               DRM_ERROR("Base block of EDID firmware \"%s\" is invalid ",
>                   name);
>               kfree(edid);
> -             err = -EINVAL;
> -             goto relfw_out;
> +             edid = ERR_PTR(-EINVAL);
> +             goto out;
>       }
>  
>       for (i = 1; i <= edid[0x7e]; i++) {
> @@ -210,19 +224,18 @@ static u8 *edid_load(struct drm_connector *connector, 
> const char *name,
>       }
>  
>       if (valid_extensions != edid[0x7e]) {
> +             u8 *new_edid;
> +
>               edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
>               DRM_INFO("Found %d valid extensions instead of %d in EDID data "
>                   "\"%s\" for connector \"%s\"\n", valid_extensions,
>                   edid[0x7e], name, connector_name);
>               edid[0x7e] = valid_extensions;
> +
>               new_edid = krealloc(edid, (valid_extensions + 1) * EDID_LENGTH,
> -                 GFP_KERNEL);
> -             if (new_edid == NULL) {
> -                     err = -ENOMEM;
> -                     kfree(edid);
> -                     goto relfw_out;
> -             }
> -             edid = new_edid;
> +                                 GFP_KERNEL);
> +             if (new_edid)
> +                     edid = new_edid;
>       }
>  
>       DRM_INFO("Got %s EDID base block and %d extension%s from "
> @@ -230,13 +243,9 @@ static u8 *edid_load(struct drm_connector *connector, 
> const char *name,
>           "external", valid_extensions, valid_extensions == 1 ? "" : "s",
>           name, connector_name);
>  
> -relfw_out:
> -     release_firmware(fw);
> -
>  out:
> -     if (err)
> -             return ERR_PTR(err);
> -
> +     if (fw)
> +             release_firmware(fw);
>       return edid;
>  }
>  
> -- 
> 1.7.9.5

-- 
Ville Syrjälä
Intel OTC
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