Re: [PATCH v2] gpu: host1x: Ignore clients initialization failure

From: Dmitry Osipenko
Date: Mon Aug 13 2018 - 13:48:32 EST


On Friday, 10 August 2018 02:12:11 MSK Dmitry Osipenko wrote:
> From time to time new bugs are popping up, causing some host1x client to
> fail its initialization. Currently a single clients initialization failure
> causes whole host1x device registration to fail, as a result a single DRM
> sub-device initialization failure makes whole DRM initialization to fail.
> Let's ignore clients initialization failure, as a result display panel
> lights up even if some DRM clients (say GR2D or VIC) fail to initialize.
> Actually VIC fails if initramfs misses the firmware file, so with this
> change a serial console isn't needed anymore to figure out why display
> isn't working.
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
>
> Changelog:
>
> v2: Added WARN_ON() that should get more attention than just a error
> message. Made clients_lock to lock around the lists modification, that is
> in line with the rest of the code.
>
> drivers/gpu/host1x/bus.c | 20 ++++++++------------
> 1 file changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
> index 815bdb42e3f0..07bb6b6c1260 100644
> --- a/drivers/gpu/host1x/bus.c
> +++ b/drivers/gpu/host1x/bus.c
> @@ -199,19 +199,23 @@ static void host1x_subdev_unregister(struct
> host1x_device *device, */
> int host1x_device_init(struct host1x_device *device)
> {
> - struct host1x_client *client;
> + struct host1x_client *client, *cl;
> int err;
>
> mutex_lock(&device->clients_lock);
>
> - list_for_each_entry(client, &device->clients, list) {
> + list_for_each_entry_safe(client, cl, &device->clients, list) {
> if (client->ops && client->ops->init) {
> err = client->ops->init(client);
> - if (err < 0) {
> + if (WARN_ON(err < 0)) {
> dev_err(&device->dev,
> "failed to initialize %s: %d\n",
> dev_name(client->dev), err);
> - goto teardown;
> +
> + /* add the client to the list of idle clients */
> + mutex_lock(&clients_lock);
> + list_add_tail(&client->list, &clients);

This shall be list_move_tail(), v3 is coming.

> + mutex_unlock(&clients_lock);