respond_to block not working in mobile version of rails application

recently i addded mobile screens to my application, after that respond_to block is not wroking

mime_type.rb

Mime::Type.register_alias "text/html", :mobile
Mime::Type.register "applications/xls", :xls

controller

def index
 @customer_ord = CustomerOrder.all
 respond_to do |format|
 format.html
 format.csv #{send_data @customer_ord.to_csv}
 format.xls #{send_data @customer_orders.to_csv(col_sep: "/t")}
 format.pdf end  end

pdf, xls links in view

<%= link_to "PDF", customer_orders_path(format: "pdf"), :target => 'blank'%>
<%= link_to "CSV", customer_orders_path(format: "csv")%>  
<%= link_to "EXCEL", customer_orders_path(format: "xls")%>

after adding mime type mobile, i am using separate mobile screens. in mobile version of application respond_to block not working.

for json methods also it was not working, i have

respond_to do |format|
format.json { render json: @price_prod.price }
end

i changed it to

render json: @price_prod.price

it is working now, but for pdf,xls generation is not working, please help

Solution

it was responding to mobile format only as i have this code in my application controller

 def prepare_for_mobile
  session[:mobile_param] = params[:mobile] if params[:mobile]
  request.format = :mobile if mobile_device?
 end

i changed it to

def prepare_for_mobile
  session[:mobile_param] = params[:mobile] if params[:mobile]
  if mobile_device? &&  request.format == :pdf
  request.format = :pdf
  elsif mobile_device? &&  request.format == :xls
  request.format = :xls 
  elsif mobile_device? &&  request.format == :csv
  request.format = :csv
  elsif mobile_device?
  request.format = :mobile
  end
end

it worked for me, but there may be a better way to resolve it.